7 results on '"Hou, Ya"'
Search Results
2. Recognition of tRNA backbone for aminoacylation with cysteine: evolution from Escherichia coli to human.
- Author
-
Ming X, Smith K, Suga H, and Hou YM
- Subjects
- Acylation, Animals, Escherichia coli, Evolution, Molecular, Genetic Code, Humans, Cysteine, RNA, Transfer genetics, RNA, Transfer metabolism
- Abstract
The underlying basis of the genetic code is specific aminoacylation of tRNAs by aminoacyl-tRNA synthetases. Although the code is conserved, bases in tRNA that establish aminoacylation are not necessarily conserved. Even when the bases are conserved, positions of backbone groups that contribute to aminoacylation may vary. We show here that, although the Escherichia coli and human cysteinyl-tRNA synthetases both recognize the same bases (U73 and the GCA anticodon) of tRNA for aminoacylation, they have different emphasis on the tRNA backbone. The E. coli enzyme recognizes two clusters of phosphate groups. One is at A36 in the anticodon and the other is in the core of the tRNA structure and includes phosphate groups at positions 9, 12, 14, and 60. Metal-ion rescue experiments show that those at positions 9, 12, and 60 are involved with binding divalent metal ions that are important for aminoacylation. The E. coli enzyme also recognizes 2'-hydroxyl groups within the same two clusters: at positions 33, 35, and 36 in the anticodon loop, and at positions 49, 55, and 61 in the core. The human enzyme, by contrast, recognizes few phosphate or 2'-hydroxy groups for aminoacylation. The evolution from the backbone-dependent recognition by the E. coli enzyme to the backbone-independent recognition by the human enzyme demonstrates a previously unrecognized shift that nonetheless has preserved the specificity for aminoacylation with cysteine.
- Published
- 2002
- Full Text
- View/download PDF
3. Amino acid activation of a dual-specificity tRNA synthetase is independent of tRNA.
- Author
-
Lipman RS, Beuning PJ, Musier-Forsyth K, and Hou YM
- Subjects
- Buffers, Protein Biosynthesis drug effects, RNA, Transfer genetics, RNA, Transfer pharmacology, Substrate Specificity drug effects, Amino Acyl-tRNA Synthetases metabolism, Cysteine metabolism, Methanococcus enzymology, Methanococcus genetics, Proline metabolism, RNA, Transfer metabolism
- Abstract
Transfer RNA can play a role in amino acid activation by aminoacyl-tRNA synthetases. For the prolyl-tRNA synthetase (ProRS) of Methanococcus jannaschii, which activates both proline and cysteine, the role of tRNA in amino acid selection and activation is of interest in the effort to understand the mechanism of the dual-specificity. While activation of proline does not require tRNA, whether or not tRNA is required in the activation of cysteine has been a matter of debate. Here, investigation of a series of buffer conditions shows that activation of cysteine occurs without tRNA in a wide-range of buffers. However, the extent of cysteine activation is strongly buffer-dependent, varying over a 180-fold range. In contrast, the extent of proline activation is much less sensitive to buffer conditions, varying over only a 36-fold range. We also find that addition of tRNA has a small threefold stimulatory effect on cysteine activation. The lack of a major role of tRNA in activation of cysteine suggests that the dual-specificity enzyme must distinguish cysteine from proline directly, without the assistance of each cognate tRNA, to achieve the necessary specificity required for protein synthesis., (Copyright 2001 Elsevier Science Ltd.)
- Published
- 2002
- Full Text
- View/download PDF
4. Prevention of mis-aminoacylation of a dual-specificity aminoacyl-tRNA synthetase.
- Author
-
Lipman RS, Wang J, Sowers KR, and Hou YM
- Subjects
- Acylation, Adenosine Triphosphate metabolism, Anticodon chemistry, Anticodon genetics, Anticodon metabolism, Base Sequence, Binding Sites, Cysteine genetics, Genetic Engineering, Kinetics, Molecular Sequence Data, Mutation genetics, Nucleic Acid Conformation, Proline genetics, Proline metabolism, RNA Editing, RNA, Transfer, Cys chemistry, RNA, Transfer, Cys genetics, RNA, Transfer, Pro chemistry, RNA, Transfer, Pro genetics, Substrate Specificity, Thermodynamics, Transcription, Genetic, Amino Acyl-tRNA Synthetases metabolism, Cysteine metabolism, Methanococcus enzymology, Methanococcus genetics, RNA, Transfer, Cys metabolism, RNA, Transfer, Pro metabolism
- Abstract
Accurate aminoacylation of tRNAs by aminoacyl-tRNA synthetase is essential for the fidelity of protein synthesis. For Methanococcus jannaschii tRNA(Pro), accuracy is difficult because the cognate prolyl-tRNA synthetase also recognizes and aminoacylates tRNA(Cys) with cysteine. We show here that the unmodified transcript of M. jannaschii tRNA(Pro) is indeed mis-acylated with cysteine. However, the origin of mis-charging is not at the anticodon or acceptor stem, the two hotspots for tRNA(Pro) and tRNA(Cys) identity determinants. Instead, replacement of the D loop in the tRNA core with that of tRNA(Cys) suppresses mis-charging with cysteine without compromising the activity of aminoacylation with proline. The reduced level of cysteine activity of the chimera is not due an editing response of the synthetase and is consistent with a relaxed sensitivity of the tRNA to the analog thiaproline in aminoacylation with cysteine. We suggest that mis-acylation is not due to the presence of cysteine determinants, but to a mis-placed 3' end into the cysteine catalytic site that activates and transfers cysteine to the tRNA. Prevention of mis-placement by alteration of the core structure or by nucleotide modifications in the tRNA illustrates a novel strategy of the dual-specificity synthetase., (Copyright 2002 Elsevier Science Limited.)
- Published
- 2002
- Full Text
- View/download PDF
5. Breaking the Stereo Barrier of Amino Acid Attachment to tRNA by a Single Nucleotide
- Author
-
Shitivelband, Svetlana and Hou, Ya-Ming
- Subjects
- *
TRANSFER RNA , *AMINO acids , *ENZYMES , *CATALYSTS - Abstract
Aminoacyl-tRNA synthetases are responsible for attaching amino acid residues to the tRNA 3′-end. The two classes of synthetases approach tRNA as mirror images, with opposite but symmetrical stereochemistries that allow the class I enzymes to attach amino acid residues to the 2′-hydroxyl group of the terminal ribose, whereas, the class II enzymes attach amino acid residues to the 3′-hydroxyl group. However, we show here that the attachment of cysteine to tRNACys by the class I cysteinyl-tRNA synthetase (CysRS) is flexible; the enzyme is capable of using either the 2′ or 3′-hydroxyl group as the attachment site. The molecular basis for this flexibility was investigated. Introduction of the nucleotide U73 of tRNACys into tRNAVal was found to confer the flexibility. While valylation of the wild-type tRNAVal by the class I ValRS was strictly dependent on the terminal 2′-hydroxyl group, that of the U73 mutant of tRNAVal occurred at either the 2′ or 3′-hydroxyl group. Thus, the single nucleotide U73 of tRNA has the ability to break the stereo barrier of amino acid attachment to tRNA, by mobilizing the 2′ and 3′-hydroxyl groups of A76 in flexible geometry with respect to the tRNA acceptor stem. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
6. Structural origins of amino acid selection without editing by cysteinyl‐tRNA synthetase.
- Author
-
Newberry, Kate J., Hou, Ya‐Ming, and Perona, John J.
- Subjects
- *
TRANSFER RNA , *ZINC ions , *BIOCHEMICAL substrates , *HISTIDINE , *LIGASES , *CYSTEINE , *CRYSTAL structure , *AMINO acids - Abstract
Cysteinyl‐tRNA synthetase (CysRS) is highly specific for synthesis of cysteinyl adenylate, yet does not possess the amino acid editing activity characteristic of many other tRNA synthetases. To elucidate how CysRS is able to distinguish cysteine from non‐cognate amino acids, crystal structures of the Escherichia coli enzyme were determined in apo and cysteine‐bound states. The structures reveal that the substrate cysteine thiolate forms a single direct interaction with a zinc ion bound at the base of the active site cleft, in a trigonal bipyramidal geometry together with four highly conserved protein side chains. Cysteine binding induces movement of the zinc ion towards substrate, as well as flipping of the conserved Trp205 indole ring to pack on the thiol side chain. The imidazole groups of five conserved histidines lie adjacent to the zinc ion, forming a unique arrangement suggestive of functional significance. Thus, amino acid discrimination without editing arises most directly from the favorable zinc–thiolate interaction, which is not possible for non‐cognate substrates. Additional selectivity may be generated during the induced‐fit conformational changes that help assemble the active site. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
7. Cysteinyl-tRNA Synthetase Mutations Cause a Multi-System, Recessive Disease That Includes Microcephaly, Developmental Delay, and Brittle Hair and Nails.
- Author
-
Kuo, Molly E., Theil, Arjan F., Kievit, Anneke, Malicdan, May Christine, Introne, Wendy J., Christian, Thomas, Verheijen, Frans W., Smith, Desiree E.C., Mendes, Marisa I., Hussaarts-Odijk, Lidia, van der Meijden, Eric, van Slegtenhorst, Marjon, Wilke, Martina, Vermeulen, Wim, Raams, Anja, Groden, Catherine, Shimada, Shino, Meyer-Schuman, Rebecca, Hou, Ya Ming, and Gahl, William A.
- Subjects
- *
CYSTEINYL-transfer RNA , *MICROCEPHALY , *HETEROGENEITY , *PHENOTYPES , *TRANSFER RNA , *CYSTEINE - Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes responsible for charging tRNA molecules with cognate amino acids. Consistent with the essential function and ubiquitous expression of ARSs, mutations in 32 of the 37 ARS-encoding loci cause severe, early-onset recessive phenotypes. Previous genetic and functional data suggest a loss-of-function mechanism; however, our understanding of the allelic and locus heterogeneity of ARS-related disease is incomplete. Cysteinyl-tRNA synthetase (CARS) encodes the enzyme that charges tRNACys with cysteine in the cytoplasm. To date, CARS variants have not been implicated in any human disease phenotype. Here, we report on four subjects from three families with complex syndromes that include microcephaly, developmental delay, and brittle hair and nails. Each affected person carries bi-allelic CARS variants: one individual is compound heterozygous for c.1138C>T (p.Gln380∗) and c.1022G>A (p.Arg341His), two related individuals are compound heterozygous for c.1076C>T (p.Ser359Leu) and c.1199T>A (p.Leu400Gln), and one individual is homozygous for c.2061dup (p.Ser688Glnfs∗2). Measurement of protein abundance, yeast complementation assays, and assessments of tRNA charging indicate that each CARS variant causes a loss-of-function effect. Compared to subjects with previously reported ARS-related diseases, individuals with bi-allelic CARS variants are unique in presenting with a brittle-hair-and-nail phenotype, which most likely reflects the high cysteine content in human keratins. In sum, our efforts implicate CARS variants in human inherited disease, expand the locus and clinical heterogeneity of ARS-related clinical phenotypes, and further support impaired tRNA charging as the primary mechanism of recessive ARS-related disease. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.