Search

In this study, characteristic features of a new regenerative 3D collagen matrix with an orientated open pore structure are studied in-vitro and in-vivo. The noncrosslinked porcine-based resorbable collagen-elastin matrix is designed to provide support during coverage procedures of localized gingival recessions and for local soft tissue augmentation around teeth and implants and is designed to provide an off-the-shelf alternative to autogenous soft tissue grafts. The in-vitro studies show that the mechanical properties (e.g. suture retention, volume recovery after cyclic compression) and the observed active cell migration into the open porous structure of the matrix fulfil essential design requirements. The in-vivo pig animal study shows that the matrix is well integrated into the surrounding tissue and replaced by newly formed autogenous soft tissue without a significant loss in tissue volume. First clinical case series are being performed to further analyse the new 3D matrix in clinical settings.

Fructansucrase enzymes polymerize the fructose moiety of sucrose into levan or inulin fructans, with [beta](2-6) and [beta](2-1) linkages, respectively. Here, we report an evaluation of fructan synthesis in three Lactobacillus gassed strains, identification of the fructansucrase-encoding genes and characterization of the recombinant proteins and fructan (oligosaccharide) products. High-performance anion-exchange chromatography and nuclear magnetic resonance analysis of the fructo-oligosaccharides (FOS) and polymers produced by the L. gassed strains and the recombinant enzymes revealed that, in situ, L. gassed strains DSM 20604 and 20077 synthesize inulin (and oligosaccharides) and levan products, respectively. L. gassed DSM 20604 is only the second Lactobacillus strain shown to produce inulin polymer and FOS in situ, and is unique in its distribution of FOS synthesized, ranging from DP2 to DP13. The probiotic bacterium L. gassed DSM 20243 did not produce any fructan, although we identified a fructansucrase-encoding gene in its genome sequence. Further studies showed that this L. gassed DSM 20243 gene was prematurely terminated by a stop codon. Exchanging the stop codon for a glutamine codon resulted in a recombinant enzyme producing inulin and FOS. The three recombinant fructansucrase enzymes characterized from three different L. gassed strains have very similar primary protein structures, yet synthesize different fructan products. An interesting feature of the L. gassed strains is that they were unable to ferment raffinose, whereas their respective recombinant enzymes converted raffinose into fructan and FOS. DOI 10.1099/mic.0.036616-0

The characterization of amylomaltase from the hyperthermophilic bacterium Thermus thermophilus HB8 (Tt AMase), the roles of the putative catalytic residues and the identification of acceptor subsites +2 and +3 in the active site are reported. The results have shown that the main catalytic machinery is the same for glycoside hydrolase family 77 (GH77) and GH13, whereas the properties of acceptor subsite +2 has distinguished the two families.

Single amino acid mutations that interchange the reaction specificities of ATPASE from acrviosyl transferase into a cyclodextrin-producing 4-alpha-glucanotransferase and CGTase from a cyclodextrin-producing 4-alpha-glucanotransferase into an acarviosyl transferase are described. In addition, the ATPase and CGTase sequences are compared using site-directed mutagenesis.

Results show that an 8.5-kilobase DNA fragment has a cluster of 10 genes and 2 of which code for enzymes involved in isoprene degradation in Rhodococcus sp. strain AD45. Data further indicate that isoprene is catobolically metabolized to carboxylate.

Glycoside hydrolase family 57 glycogen branching enzymes (GH57GBE) catalyze the formation of an α‐1,6 glycosidic bond between α‐1,4 linked glucooliogosaccharides. As an atypical family, a limited number of GH57GBEs have been biochemically characterized so far. This study aimed at acquiring a better understanding of the GH57GBE family by a systematic sequence‐based bioinformatics analysis of almost 2500 gene sequences and determining the branching activity of several native and mutant GH57GBEs. A correlation was found in a very low or even no branching activity with the absence of a flexible loop, a tyrosine at the loop tip, and two β‐strands. [ABSTRACT FROM AUTHOR]

A study was conducted to explore the evolutionary input required to efficiently interchange specificities of glycoside hydrolase family 13 (GH13). The possibility to effectively interchange reaction specificities within GH13 is demonstrated by conversion of a transglycosylase into an efficient hydrolase through combined saturation mutagenesis.

Research has been conducted on cyclodextrin glycosyltransferase which catalyzes transglycosylation reactions. The authors have identified amino acid residues which are important for transglycosylation reaction specificity, and have described the use of error-prone PCR mutagenesis for screening Bacillus circulans strain 251 cyclodextrin glycosyltransferase's mutants with increase hydrolytic activity.