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Background. Serine proteinase inhibitors, clade B, member 3 (SerpinB3) and B4 are highly similar in amino acid sequences and associated with inflammation regulation. We investigated SerpinB3 and B4 expression and their roles in chronic rhinosinusitis with nasal polyps (CRSwNP). Methods. The expression of SerpinB3 and B4 in nasal mucosa tissues, brush cells, and secretions from CRSwNP patients was measured, and their regulation by inflammatory cytokines were investigated. Their functions were also analyzed using air–liquid interface (ALI)-cultured primary human nasal epithelial cells (HNECs) and transcriptomic analysis. Results. Both SerpinB3 and B4 expression was higher in nasal mucosa, brush cells, and secretions from eosinophilic (E) CRSwNP and nonECRSwNP patients than in healthy controls. Immunofluorescence staining indicated that SerpinB3 and B4 were primarily expressed in epithelial cells and their expression was higher in CRSwNP patients. SerpinB3 and B4 expression was upregulated by interleukin-4 (IL-4), IL-5, IL-6, and IL-17a. Transcriptomic analysis identified differentially expressed genes (DEGs) in response to recombinant SerpinB3 and B4 stimulation. Both the DEGs of SerpinB3 and B4 were associated with disease genes of nasal polyps and inflammation in DisGeNET database. Pathway enrichment indicated that downregulated DEGs of SerpinB3 and B4 were both enriched in cytokine–cytokine receptor interactions, with CXCL8 as the hub gene in the protein–protein interaction networks. Furthermore, CXCL8/IL-8 expression was downregulated by recombinant SerpinB3 and B4 protein in ALI-cultured HNECs, and upregulated when knockdown of SerpinB3/B4. Conclusion. SerpinB3/B4 expression is upregulated in nasal mucosa of CRSwNP patients. SerpinB3/B4 may play an anti-inflammatory role in CRSwNP by inhibiting the expression of epithelial cell-derived CXCL8/IL-8. [ABSTRACT FROM AUTHOR]

In the current paper, two presumable mechanisms of protein folding are discussed; one of them, the 'nucleation mechanism', is exemplified by 3β-corner domains containing proteins, while the other, 'structural units mechanism', is exemplified by serine proteases. The analysis of the spatial structure of 3β-corners and of the common features of the amino acid sequences encoding them made it possible to conclude, that 3β-corners are capable of assuming their unique structures on their own and can serve as the nuclei or preformed structural units in the process of protein folding. The high order protein structures may be obtained by the further successive addition of β strands to a 3β-corner acting as a nucleus, according to certain rules and restrictions. On the other hand, 3β-corner may serve as a preformed structural unit, and the association of two 3β-corners may result in the formation of such 3D structures, which can be found in the domains of serine proteases and similar proteins. [ABSTRACT FROM AUTHOR]

Background: In this paper, we describe cDNA cloning of a new anionic trypsin and a collagenolytic serine protease from king crab Paralithodes camtschaticus and the elucidation of their primary structures. Constructing the phylogenetic tree of these enzymes was undertaken in order to prove the evolutionary relationship between them. Results: The mature trypsin PC and collagenolytic protease PC contain 237 (Mcalc 24.8 kDa) and 226 amino acid residues (Mcalc 23.5 kDa), respectively. Alignments of their amino acid sequences revealed a high degree of the trypsin PC identity to the trypsin from Penaeus vannamei (approximately 70%) and of the collagenolytic protease PC identity to the collagenase from fiddler crab Uca pugilator (76%). The phylogenetic tree of these enzymes was constructed. Conclusions: Primary structures of the two mature enzymes from P. camtschaticus were obtained and compared with those of other proteolytic proteins, including some enzymes from brachyurans. A phylogenetic analysis was also carried out. These comparisons revealed that brachyurins are closely related to their vertebrate and bacterial congeners, occupy an intermediate position between them, and their study significantly contributes to the understanding of the evolution and function of serine proteases. [ABSTRACT FROM AUTHOR]

Abstract: Aspergillus versicolor is common on moldy building materials. Asp v 13, the principal allergen is produced by strains collected from across Canada. In this paper, we report a 1833bp Asp v 13 open reading frame predicted to encode a protein of 403 amino acids in length with three introns. A BLAST search of Asp v 13, a phylogenic tree calculation and alignment with its homologous proteins from other species indicated that Asp v 13 is a secretory, subtilisin-like serine protease widely distributed in Aspergillus species. His-tagged Asp v 13 was over-expressed in Escherichia coli and purified using Ni-NTA columns with a yield of 1mg/L. Based on immuno binding assay of recombinant protein both antibodies developed against the natural protein, and human sera IgE, the recombinant protein was similar to the natural form. Six IgE- and seven IgG-binding epitopes were also identified with selected human sera along the entire amino acid sequence of Asp v 13. Most residues binding these epitopes are exposed on the surface and correspond to charged regions of the molecule. [Copyright &y& Elsevier]

Abstract: FVII is a vitamin K dependent serine protease that plays a key role in extrinsic coagulation pathway. In this paper, we report the full-length cDNA sequences of rhesus monkey FVII. The full-length cDNA has 2424 bp, and predicts an open reading frame of 1416 bp corresponding to 472 amino acids. The deduced protein sequence of rhesus monkey FVII indicates the functional domains including signal peptide, Gla domain, two EGF domains, and catalytic domain. Rhesus monkey FVII is highly homologous to human FVII with amino acid identity of 91.0%. Comparison of three-dimensional protein structure shows high conservation between them. The important functional sites such as the N-terminal γ-carboxyglutamic acids of the Gla domain, the Ca2+ binding region of the EGF I domain, the TF binding region, the active site binding cleft, and the macromolecular substrate binding exosite of trypsin domain are all well conserved in FVII of rhesus monkey. Prothrombin time test shows rhesus monkey FVII has a similar clotting time with that of human. This study of rhesus monkey FVII might be helpful for understanding the function compatibility of human and rhesus monkey FVII, which is beneficial for the study of xenotransplantation. [Copyright &y& Elsevier]

Protease (PPL) was isolated from Pseuderanthemum latifolium B. Hansen and had a molecular mass of 70 kDa. The N-terminal sequence of PPL showed 70-80% similarity with of subtilisin-like serine proteases from plants, but it did not show any sequence homology with known plant proteases. Serine protease inhibitors (PMSF, DFP) effectively blocked about 90% of PPL activity. PPL was highly activity at the pH range from 6 to 9 and temperatures from 50 °C to 80 °C, with an optimum at pH 7.0 and temperatures 70 °C. PPL had stability in a variety of pH, temperature, surfactant and oxidizing agents. PPL with concentration of 2.5 µg completely hydrolyzed the Aα-chain of fibrinogen within 5 min and hydrolyzed the Bβ and the γ-chain after 10 h. Fibrin also was strong hydrolyzed by PPL with concentration of 0.3 µg. Thus, PPL is a unique serine protease, which it had strong fibrino(geno)lytic activities. [ABSTRACT FROM AUTHOR]

Biochemical and biological functions of proteins are the product of both the overall fold of the polypeptide chain, and, typically, structural motifs made up of smaller numbers of amino acids constituting a catalytic center or a binding site that may be remote from one another in amino acid sequence. Detection of such structural motifs can provide valuable insights into the function(s) of previously uncharacterized proteins. Technically, this remains an extremely challenging problem because of the size of the Protein Data Bank (PDB) archive. Existing methods depend on a clustering by sequence similarity and can be computationally slow. We have developed a new approach that uses an inverted index strategy capable of analyzing >170,000 PDB structures with unmatched speed. The efficiency of the inverted index method depends critically on identifying the small number of structures containing the query motif and ignoring most of the structures that are irrelevant. Our approach (implemented at motif.rcsb.org) enables real-time retrieval and superposition of structural motifs, either extracted from a reference structure or uploaded by the user. Herein, we describe the method and present five case studies that exemplify its efficacy and speed for analyzing 3D structures of both proteins and nucleic acids. Author summary: The Protein Data Bank (PDB) provides open access to more than 170,000 three-dimensional structures of proteins, nucleic acids, and biological complexes. Similarities between PDB structures give valuable functional and evolutionary insights but such resemblance may not be evident at sequence or global structure level. Throughout the database, there are recurring structural motifs—groups of modest numbers of residues in proximity that, for example, support catalytic activity. Identification of common structural motifs can reveal similarities between proteins and serve as fingerprints for spatial configurations of amino acids, such as the His-Asp-Ser catalytic triad found in serine proteases or the zinc coordination site found in Zinc Finger DNA-binding domains. We present a highly efficient yet flexible strategy that allows users for the first time to search for arbitrary structural motifs across the entire PDB archive in real-time. Our approach scales favorably with the increasing number and complexity of deposited structures, and, also, has the potential to be adapted for other applications in a macromolecular context. [ABSTRACT FROM AUTHOR]

Jellyfish is a common toxic zooplankton in ocean. We successfully captured a kind of jellyfish 200 m underwater in Antarctica, and identified it as a jellyfish Cyanea sp. through morphological examination and MT-CO1 phylogenetic analysis. A total of 40,468 unigenes were harvested through transcriptome sequencing. We also successfully annotated 12,955 (32.01%) unigenes with the NR database, 10,882 (26.89%) unigenes with the SWISSPROT database, 4951 (12.23%) unigenes with the GO database, and 4901 (12.11%) unigenes with the KEGG database. In the proteomic analysis, a total of 11,159 peptides and 2630 proteins were harvested using the constructed transcriptome as the database. A number of 771 (29.31%) and 841 (31.98%) proteins were annotated against the GO and KEGG database, respectively. Moreover, a number of 29 toxic proteins matched from the 145 toxin-related unigenes were successfully screened, including 6 metalloproteinases, 4 phospholipases, 2 serine proteases, 1 serine protease inhibitor, 7 toxin-related venom and 9 other toxins. Our study is the first to identify a polar jellyfish Cyanea sp. with transcriptomics and proteomics, and these data can further serve as a public database for the identification of potential polar jellyfish-derived lead compounds feasibly functioning in the cold environment. With increasing discussions on marine biodiversity and global warming, polar species have gradually become a focus for research. To the best of our knowledge, there is only one paper in pubMed about the mitochondrial genome of the Antarctic stalked jellyfish Haliclystus antarcticus Pfeffer. In this study, we captured a type of jellyfish (named BD-4) from the Southern Ocean (60°29′57" S, 52°11′44"W) on the scientific expedition ship "Xue Long" at the end of 2016. Although the samples were stored and transported by the ship at only −20 °C for more than two month, we successfully extracted the total RNA, and performed molecular species identification and combined analyses of de novo transcriptomics and proteomics. In addition to conventional bioinformatics techniques such as GO and KEGG annotation, we screened and listed toxic proteins, aligned the sequences, simulated three-dimensional structures and performed molecular phylogenetic analysis for typical components, including metalloproteinase and serine proteinase. Our study is the first to identify a polar jellyfish Cyanea sp. with de novo transcriptomics and proteomics, and these data can further serve as a public database for the identification of potential polar jellyfish-derived lead compounds. Species identification. (A) Geographical distribution (left) of the jellyfish captured from Antarctica (60°29′57 "S, 52°11′44" W) and image of the jellyfish that was preliminarily named BD-4 (right). The sampling location is marked in red circles. (B) Phylogenetic tree constructed using mtDNA sequences of cytochrome c oxidase subunit I (MT-COI, CO1) by using MEGA 7 with the Neighbor-Joining method. BD-4 is marked with red circles, lophotrochozoa are marked with dark blue circles, cnidaria are marked with light blue circles and the identity values are indicated on the right of each species name. (C) Two amino acid sequences of CO1 from Cyanea tzetlinii and Cyanea capillata aligned with the CO1 amino acids of BD-4 transformed from the DNA sequence by blastx. At the bottom of the columns, asterisks (*) show conserved positions, and colons (:) show conserved substitutions and points. (D) Phylogenetic tree constructed using the CO1 amino acid sequences of BD-4 and 7 other species using using MEGA 7 with the Neighbor-Joining method. BD-4 is marked with red circles, and the identity values are indicated to the right of each species name. Unlabelled Image • We have luckily captured an Antarctic jellyfish by the Chinese "Xuelong" scientific ship, and naturally did the investigations on it by CO1 molecular identification, combined analysis of transcriptomics and proteomics, as well as its toxin screening. The sample is very precious and this study is the first to identify the polar jellyfish, and its toxin screening. • Our study is the first to identify a polar jellyfish Cyanea sp. with transcriptomics and proteomics, and these data can further serve as a public database for the identification of potential polar jellyfish-derived lead compounds that feasibly function well in the cold environment. [ABSTRACT FROM AUTHOR]

Vacuoles are useful materials with antimicrobial and anticancerous properties. Vacuolar proteins can discompose macromolecules from the outside of yeast cells. The objective of this study was to determine the function of a protein transported into a vacuole. Specifically, cytosolic protein aldehyde dehydrogenase 6 (ALD6) was used for the delivery to the vacuole. To transport cytosolic protein to the vacuole in this study, a transfer vector including a signal peptide sequence isolated from vacuolar protein proteinase A was designed. A signal peptide is an amino acid sequence in front of the transported protein. Signal peptides have various delivery pathways according to the kind of signal sequence they contain. They play important roles in transporting proteins to organelles, in cellular mechanisms, and the transfer of protein outside and inside eukaryotes. Thus, we focused on the design of a transfer vector containing a signal peptide sequence isolated from the DNA sequence of proteinase A (PEP4). In addition, this study evaluated the expression level of cytosolic ALD6 after being transported into the yeast vacuole. Our results showed that the developed transfer vector was useful for delivering proteins to vacuole by using signal peptide sequence. Therefore, this transfer vector might be used as a tool to deliver target proteins to organelles of interest in eukaryotes. [ABSTRACT FROM AUTHOR]

Macrobrachium carcinus (Linnaeus, 1758) is a species of freshwater shrimp widely distributed from Florida southwards to southern Brazil, including southeast of Mexico. In the present work, we identified a putative trypsin-like protease cDNA fragment of 736 nucleotides from M. carcinus hepatopancreas tissue by the 3′RACE technique and compared the deduced amino acid sequence to other trypsin-related proteases to describe its structure and function relationship. The bioinformatics analyses showed that the deduced amino acid sequence likely corresponds to a trypsin-like protease closely related to brachyurins, which comprise a subset of serine proteases with collagenolytic activity found in crabs and other crustacea. The M. carcinus trypsin-like protease sequence showed a global sequence identity of 94% with an unpublished trypsin from Macrobrachium rosenbergii (GenBank accession no. AMQ98968), and only 57% with Penaeus vannamei trypsin (GenBank accession no. CAA60129). A detailed analysis of the amino acid sequence revealed specific differences with crustacean trypsins, such as the sequence motif at the beginning of the mature protein, activation mechanism of the corresponding zymogen, amino acid residues of the catalytic triad and residues responsible for substrate specificity [ABSTRACT FROM AUTHOR]

Granzymes are a family of serine proteases found in the lytic granules of cytotoxic T lymphocytes and natural killer (NK) cells, which are involved in killing of susceptible target cells. Most information on granzymes and their enzymatic specificities derive from studies in humans and mice. Although granzymes shared by both species show a high level of conservation, the complement of granzyme genes differs between the species. The aim of this study was to identify granzyme genes expressed in cattle, determine their genomic locations and analyse their sequences to predict likely functional specificities. Orthologues of the five granzyme genes found in humans (A, B, H, K and M) were identified, as well a novel gene designated granzyme O, most closely related to granzyme A. An orthologue of granzyme O was found in pigs and a non-function version was detected in the human genome. Use of specific PCRs demonstrated that all of these genes, including granzyme O, are expressed in activated subsets of bovine lymphocytes, with particularly high levels in CD8 T cells. Consistent with findings in humans and mice, the granzyme-encoding genes were located on three distinct genomic loci, which correspond to different proteolytic enzymatic activities, namely trypsin-like, chymotrypsin-like and metase-like. Analysis of amino acid sequences indicated that the granzyme proteins have broadly similar enzymatic specificities to their human and murine counterparts but indicated that granzyme B has a different secondary specificity. These findings provide the basis for further work to examine their role in the cytotoxic activity of bovine CD8 T cells. [ABSTRACT FROM AUTHOR]

Seryl-histidine dipeptide (Ser-His) has been recognized as the shortest peptide with hydrolysis cleavage activity; however, its protein cleavage spectrum has not yet been fully explored. Here, four differently folded proteins were treated with Ser-His, and the digestion products were evaluated with high-resolution mass spectrometry. The cleavage efficiency and cleavage propensity of Ser-His against these protein substrates were calculated at both the primary and secondary sequence levels. The above experiments show that Ser-His cleaves a broad spectrum of substrate proteins of varying secondary structures. Moreover, Ser-His could cleave at all 20 amino acids with different efficiencies according to the protein, which means that Ser-His has the original digestion function of serine proteases. Furthermore, we collected and compared the catalytic sites and cleavage sites of 340 extant serine proteases derived from 17 representative organisms. A consensus motif Ser-[X]-His was identified as the major pattern at the catalytic sites of serine proteases from all of the organisms represented except Danio rerio, which uses Ser-Lys instead. This finding indicates that Ser-His is the core component of the serine protease catalytic site. Moreover, our analysis revealed that the cleavage sites of modern serine proteases have become more specific over the evolutionary history of this family. Based on the above analysis results, it could be found that Ser-His is likely the original serine protease and maybe the evolutionary core of modern serine proteases. [ABSTRACT FROM AUTHOR]

Background: Development of sensitive sequence search procedures for the detection of distant relationships between proteins at superfamily/fold level is still a big challenge. The intermediate sequence search approach is the most frequently employed manner of identifying remote homologues effectively. In this study, examination of serine proteases of prolyl oligopeptidase, rhomboid and subtilisin protein families were carried out using plant serine proteases as queries from two genomes including A. thaliana and O. sativa and 13 other families of unrelated folds to identify the distant homologues which could not be obtained using PSI-BLAST. Methodology/Principal Findings: We have proposed to start with multiple queries of classical serine protease members to identify remote homologues in families, using a rigorous approach like Cascade PSI-BLAST. We found that classical sequence based approaches, like PSI-BLAST, showed very low sequence coverage in identifying plant serine proteases. The algorithm was applied on enriched sequence database of homologous domains and we obtained overall average coverage of 88% at family, 77% at superfamily or fold level along with specificity of ∼100% and Mathew’s correlation coefficient of 0.91. Similar approach was also implemented on 13 other protein families representing every structural class in SCOP database. Further investigation with statistical tests, like jackknifing, helped us to better understand the influence of neighbouring protein families. Conclusions/Significance: Our study suggests that employment of multiple queries of a family for the Cascade PSI-BLAST searches is useful for predicting distant relationships effectively even at superfamily level. We have proposed a generalized strategy to cover all the distant members of a particular family using multiple query sequences. Our findings reveal that prior selection of sequences as query and the presence of neighbouring families can be important for covering the search space effectively in minimal computational time. This study also provides an understanding of the ‘bridging’ role of related families. [ABSTRACT FROM AUTHOR]

A new member of the genus Nepovirus was isolated from blueberry in Japan. The virus was associated with latent infection of blueberry trees and provisionally named blueberry latent spherical virus (BLSV). BLSV was found to have isometric particles approximately 30 nm in diameter, which were composed of a single coat protein (CP) of 55 kDa. The viral genome consisted of two positive-sense single-stranded RNA species (RNA1 and RNA2), which were 7,960 and 6,344 nucleotides (nt) long, respectively. The organization of RNA1 and RNA2 was similar to that of nepoviruses. The 3′ non-coding regions of RNA1 and RNA2 were 1,379 nt and 1,392 nt long, respectively. The amino acid sequences of the BLSV polymerase and CP shared the highest amino acid sequence similarities with those of the subgroup C nepoviruses (57% and 43%, respectively). Additionally, the BLSV genome, in contrast to other nepovirus genomes, was predicted to encode a serine protease. [ABSTRACT FROM AUTHOR]

Identifying elements of protein structures that create differences in protein-ligand binding specificity is an essential method for explaining the molecular mechanisms underlying preferential binding. In some cases, influential mechanisms can be visually identified by experts in structural biology, but subtler mechanisms, whose significance may only be apparent from the analysis of many structures, are harder to find. To assist this process, we present a geometric algorithm and two statistical models for identifying significant structural differences in protein-ligand binding cavities. We demonstrate these methods in an analysis of sequentially nonredundant structural representatives of the canonical serine proteases and the enolase superfamily. Here, we observed that statistically significant structural variations identified experimentally established determinants of specificity. We also observed that an analysis of individual regions inside cavities can reveal areas where small differences in shape can correspond to differences in specificity. [ABSTRACT FROM AUTHOR]

Mutations in rumi result in a temperature-sensitive loss of Notch signaling in Drosophila. Drosophila Rumi is a soluble, endoplasmic reticulum-retained protein with a CAP10 domain that functions as a protein O-glucosyltransferase. In human and mouse genomes, three potential Rumi homologues exist: one with a high degree of identity to Drosophila Rumi (52%), and two others with lower degrees of identity but including a CAP10 domain (KDELC1 and KDELC2). Here we show that both mouse and human Rumi, but not KDELC1 or KDELC2, catalyze transfer of glucose from UDP-glucose to an EGF repeat from human factor VII. Similarly, human Rumi, but not KDELC1 or KDELC2, rescues the Notch phenotypes in Drosophila rumi clones. During characterization of the Rumi enzymes, we noted that, in addition to protein O-glucosyltransferase activity, both mammalian and Drosophila Rumi also showed significant protein O-xylosyltransferase activity. Rumi transfers Xyl or glucose to serine 52 in the O-glucose consensus sequence (50CASSPC55) of factor VII EGF repeat. Surprisingly, the second serine (S53) facilitates transfer of Xyl, but not glucose, to the EGF repeat by Rumi. EGF16 of mouse Notch2, which has a diserine motif in the consensus sequence (587CYSSPC592), is also modified with either O-Xyl or O-glucose glycans in cells. Mutation of the second serine (S590A) causes a loss of O-Xyl but not O-glucose at this site. Altogether, our data establish dual substrate specificity for the glycosyltransferase Rumi and provide evidence that amino acid sequences of the recipient EGF repeat significantly influence which donor substrate (UDP-glucose or UDP-Xyl) is used. [ABSTRACT FROM AUTHOR]

Serine proteinases and Kunitz-type inhibitors are widely represented in the venoms of snakes belonging to different genera. During the studies of the venoms of snakes inhabiting Russia, we have cloned cDNAs coding for novel proteins of these families. A novel serine proteinase that we named nikobin was identified in the venom gland of the Nikolsky viper. The amino acid sequence of nikobin deduced from the cDNA sequence slightly differs from those of the serine proteinases found in other snakes, displaying 15 unique amino acid substitutions. This is the first serine proteinase from a viper of the Vipera genus for which the complete amino acid sequence has been determined. A cDNA coding for a Kunitz-type inhibitor has also been cloned. The deduced amino acid sequence of the inhibitor displays overall homology to the already known sequences of analogous proteins from vipers of the Vipera genus. However, several unusual amino acid substitutions that can cause a change of the inhibitor activity have been detected. [ABSTRACT FROM AUTHOR]

Motivation: Current computational approaches to function prediction are mostly based on protein sequence classification and transfer of annotation from known proteins to their closest homologous sequences relying on the orthology concept of function conservation. This approach suffers a major weakness: annotation reliability depends on global sequence similarity to known proteins and is poorly efficient for enzyme superfamilies that catalyze different reactions. Structural biology offers a different strategy to overcome the problem of annotation by adding information about protein 3D structures. This information can be used to identify amino acids located in active sites, focusing on detection of functional polymorphisms residues in an enzyme superfamily. Structural genomics programs are providing more and more novel protein structures at a high-throughput rate. However, there is still a huge gap between the number of sequences and available structures. Computational methods, such as homology modeling provides reliable approaches to bridge this gap and could be a new precise tool to annotate protein functions.Results: Here, we present Active Sites Modeling and Clustering (ASMC) method, a novel unsupervised method to classify sequences using structural information of protein pockets. ASMC combines homology modeling of family members, structural alignment of modeled active sites and a subsequent hierarchical conceptual classification. Comparison of profiles obtained from computed clusters allows the identification of residues correlated to subfamily function divergence, called specificity determining positions. ASMC method has been validated on a benchmark of 42 Pfam families for which previous resolved holo-structures were available. ASMC was also applied to several families containing known protein structures and comprehensive functional annotations. We will discuss how ASMC improves annotation and understanding of protein families functions by giving some specific illustrative examples on nucleotidyl cyclases, protein kinases and serine proteases.Availability: http://www.genoscope.fr/ASMC/.Contact: raquelcm@dcc.ufmg.br; kbastard@genoscope.cns.fr; artigue@genoscope.cns.frSupplementary information: Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Xylem plays a role not only in the transport of water and nutrients but also in the regulation of growth and development through the transport of biologically active substances. In addition to mineral salts, xylem sap contains hormones, organic nutrients and proteins. However, the physiological functions of most of those substances remain unclear. To explore genes involved in xylem sap production, we identified Arabidopsis genes expressed in the root stele of the root hair zone from gene-trap lines by randomly inserting the β-glucuronidase gene into the genome. Among 26 000 gene-trap lines, we found that 10 lines had β-glucuronidase (GUS) staining predominantly in the root stele of the root hair zone and no GUS staining in the shoots. Of these 10 lines, 2 lines showed that gene-trap tags inserted into the promoter region of the same gene, denoted Arabidopsis thaliana subtilase 4.12( AtSBT4.12). Analysis of AtSBT4.12 promoter using an pAtSBT4.12::β-glucuronidase transgenic line showed that the AtSBT4.12 gene was expressed only in the root stele of the root hair zone. AtSBT4.12 expression in roots was increased by application of methyl jasmonate. Subtilase proteins are commonly detected in proteomic analyses of xylem sap from various plant species, including Brassica napus, a relative of Arabidopsis. These results suggest that AtSBT4.12 may be a protein localized in the apoplast of root stele including xylem vessel and involved in stress responses in Arabidopsis roots. [ABSTRACT FROM AUTHOR]

Culicoides spp. are vectors of several infectious diseases of veterinary importance and a major cause of allergy in horses and other livestock. Their saliva contains a number of proteins which enable blood feeding, enhance disease transmission and act as allergens. We report the construction of a novel cDNA library from Culicoides nubeculosus linked to the analysis of abundant salivary gland proteins by mass spectrometry. Fifty-four novel proteins sequences are described including those of the enzymes maltase, hyaluronidase and two serine proteases demonstrated to be present in Culicoides salivary glands, as well as several members of the D7 family and protease inhibitors with putative anticoagulant activity. In addition, several families of abundant proteins with unknown function were identified including some of the major candidate allergens that cause insect bite hypersensitivity in horses. [ABSTRACT FROM AUTHOR]

Abstract  A serine protease from Bothrops atrox (Peruvian specimen’s venom) was isolated in two chromatographic steps in LC molecular exclusion and reverse phase-HPLC. This protein was denominated Ba III-4 (33,080.265 Da determinated by MALDI-TOF mass spectrometry) and showed pI of 5.06, Km 0.2 � 10−1  M and the V m�x 4.1 � 10−1 nmoles p-NA/lt/min on the synthetic substrate BapNA. Ba III-4 also showed ability to coagulate bovine fibrinogen. The serine protease was inhibited by soyben trypsin inhibitor and DA2II, which is an anti-hemorrhagic factor isolated from the opossum specie Didelphis albiventris. The primary structure of Ba III-4 showed the presence of His(44), Asp(94) and Ser(193) residues in the corresponding positions to the catalytic triad established in the serine proteases and Ser(193) are inhibited by phenylmethylsulfonylfluoride (PMSF). Amino acid analysis showed a high content of Asp, Glu, Gly, Ser, Ala and Pro, as well as 12 half-cysteine residues. Ba III-4 contained 293 amino acid residues and the primary structure of VIGGDECDIN EHPFLAFMYY SPRYFCGMTL INQEWVLTAA HCRYFCGMTL IHLGVHRESE KANYDEVRRF PKEKYFIFCD NNFTDDEVDK DIMLIRLDKP VSNSEHIAPL SLPSNPPSVG SVCRIMGWGQ TTTSPIDVLS PDEPHCANIN LFDNTVCHTA HPQVANTRTS TDTLCAGDLQ GGRDTCNGDS GGPLICNEQL HGILSWGGDP CAQPNKPAFY TKVYYFDHPW IKSIIAGNKK TVNFTCPPLR SDAKDDSTTY INQEWDWVLT AEHCDRTHMR NSFYDYSSIN SDS. Titration experiments did not show the presence of free sulfhydryl groups after 4 h incubation, nor were differences found in relation to titration kinetics in the presence of nondenaturating buffer. The isolation of this protein, Ba III-4, is of potential interest for the understanding of the pathomechanism of the snake venom action and for the identification of new blood coagulation enzymes of natural sources. [ABSTRACT FROM AUTHOR]

A trypsin-type serine proteinase (WSP) was purified previously from the sarcoplasmic fraction of skeletal muscle of white croaker ( Argyrosomus argentatus) by Yanagihara et al. ((1991) Nippon Suisan Gakaishi, 57, 133–142). However, further research on WSP was not carried out. In the present study, we determined the N-terminal amino acid sequence of this enzyme (27 amino acid residues), which revealed relatively high identity in the conserved region to other trypsin-type serine proteinases. Degradation action of WSP on neuropeptides is also reported in this manuscript. The results show that WSP only cleaves at the carboxyl side of Arg or Lys residue of the peptides, especially between dibasic amino acid residues such as Arg—Arg and Arg—Lys. [ABSTRACT FROM AUTHOR]

A family of hypothetical proteins, identified predominantly from archaeal genomes, has been analyzed in order to understand its functional characteristics. Using extensive sequence similarity searches it is inferred that this family is remotely related (best sequence identity is 19%) to ClpP proteinases that belongs to serine proteinase class. This family of hypothetical proteins is referred to as SDH proteinase family based on conserved sequential order of Ser, Asp and His residues and predicted serine proteinase activity. Results of fold recognition of SDH family sequences confirmed the remote relationship between SDH proteinases and Clp proteinases and revealed similar tertiary location of putative catalytic triad residues critical for serine proteinase function. However, the best sequence alignment we could obtain suggests that while catalytic Ser is conserved across Clp and SDH proteinases the location of the other catalytic triad residues, namely, His and Asp are swapped in their amino acid alignment positions and hence in 3-D structure. The evidence of conserved catalytic triad suggests that SDH could be a new family of serine proteinases with the fold of Clp proteinase, however sharing the catalytic triad order of carboxypeptidase clan. Signal peptide sequence identified at the N-terminus of some of the homologues suggests that these might be secretory serine proteinases involved in cleavage of extracellular proteins while the remote homologues, ClpP proteinases, are known to work in intracellular environment. [ABSTRACT FROM AUTHOR]

Previously we isolated and characterized a membrane-bound, arginine-specific serine protease from pig intestinal mucosa [J. Biol Chem 269, 32985–32991 (1994)]. For further characterization of this type of enzyme, we cloned a cDNA from rat intestinal mucosa encoding the precursor of a similar protease. The partial amino acid sequences determined for the pig enzyme were found to be shared almost completely by the rat enzyme. The serine protease domain of the rat enzyme, heterologously expressed in Escherichia coli, specifically cleaved Arg (or Lys)-X bonds with a marked preference for Arg-Arg or Arg-Lys, similar to the pig enzyme. The mRNA for the rat enzyme was shown to be distributed mainly in intestine, and the enzyme was detected in the duodenal mucosa as a 70 kDa protein. Immunohistochemical analysis of the small intestinal tissue showed that the enzyme is localized mainly on brushborder membranes. [ABSTRACT FROM AUTHOR]

A cysteine protease, phytolacain R from full-growth greenish fruits of pokeweed, Phytolacca americana L, was purified to electrophoretic homogeneity by a simple purification procedure employing CM-Sepharose ion-exchange chromatography. The enzyme was present in low content in the young fruits about 50 d after flowering but gradually accumulated in growing fruits. Its molecular mass was estimated to be ca. 23 kDa by SDS-PAGE, and its sugar content was zero. Its amino acid sequence was established by automated sequence analysis of the peptides obtained by cleavage with Achromobacter protease I, chymotrypsin, trypsin, and cyanogen bromide. The enzyme is composed of 218 amino acid residues, of which it shares 110 residues (50%) with papain, 104 (47%) with actinidain, and 87 (40%) with stem bromelain. The amino acid residues forming the substrate-binding the S2 pocket of papain, Tyr61, Tyr67, Pro68, Trp69, Val133, and Phe207, were predicted to be replaced by Gly, Trp, Met, His, Ala, and Met in phytolacain R, respectively. As a consequence of these substitutions, the S2 pocket is expected to be less hydrophobic in phytolacain R than in papain. [ABSTRACT FROM AUTHOR]

The primary structure of light chain of α-clostripain was determined by sequence analysis of peptides derived from tryptic digests purified by reverse-phase high-performance liquid chromatography. The 22 isolated tryptic peptides were aligned by peptides derived from chymotryptic and staphylococcal V8 proteinase digests. The light chain contains 133 amino acids residues and has a relative molecular mass of 15400. The prediction of its secondary structure is given. [ABSTRACT FROM AUTHOR]

The maturation of dental enamel succeeds the degradation of organic matrix. Inhibition studies have shown that this degradation is accomplished by a serine-type proteinase. To isolate and characterize cDNA clones encoding this proteinase, we used two degenerate primer approaches to amplify part of the coding region using polymerase chain-reaction (PCR). First, we purified the proteinase from porcine transition-stage enamel matrix and characterized it by partial protein sequencing. The enzyme was isolated from the neutral soluble enamel extract by successive ammonium sulfate precipitations, hydroxyapatite HPLC, reverse-phase HPLC, DEAE ion exchange, and affinity chromatography with a Benzamidine Sepharose 6B column. The intact protein and lysylendopeptidase-generated cleavage products were characterized by amino acid sequence analyses. Degenerate oligonucleotide primers encoding two of the polypeptide sequences were synthesized. In a complementary strategy, degenerate oligonucleotide primers were designed against highly conserved active-site regions of chymotrypsin-like proteinases. Both approaches yielded PCR amplification products that served as probes for screening a porcine enamel organ epithelia-specific cDNA library. The longest full-length clone is 1133 nucleotides and encodes a preproprotein of 254 amino acids. We designate this protein enamel matrix serine proteinase 1 or EMSP1. The active protein has 224 amino acids, an isotope-averaged molecular mass of 24.1 kDa, and an isoelectric point of 6.0. Multiple-tissue Northern analysis indicates that EMSP1 is a tooth-specific protein. Gelatin enzymography shows a dramatic increase in EMSP1 activity in the transition-stage enamel matrix. EMSP1 is most homologous to kallikriens and trypsins. [ABSTRACT FROM AUTHOR]