(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Proteobacteria: NE > Gammaproteobacteria: NE > Pseudomonadales: NE > Pseudomonadaceae: NE > Pseudomonas: NE > Pseudomonas sp.: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MNQSLGVLRLTRGVIALALASVASGCSSTGADRTAATPAAANPAATEPVK WECPAGYEVKEGLNVDFPHKGMKRAFIVYPAKNVSGPAPVWVPMTGSVES TNDNLTVARSGANSILADHGYTVIAPVRACANQDPNIRGERCNGPGSNGW NWNPWFEGRAADPSGEHWKNDEGPDSSFFVAMVQCVGTKYKLDARRLFLG GISSGGTMTNRALLFRSNFWAGGLPISGEWYVTSDDGTPLSFDDARAAVA AAPTKIHQGRVGPYPLPAKVGPLIVMTVWGGEKDLWNCTRPDGSRFLCAD YRPSTQAGSNFFSAQPDVVHVACSSTHGHMWPQLNTQEFNRWALDTLASH PKGSDPRSFKLTQPPEGYTCHVGPFTGLY
The ever-increasing production and use of polyvinyl alcohol (PVA) threaten our environment. Yet PVA can be assimilated by microbes in two steps: oxidation and cleavage. Here we report novel alpha/beta-hydrolase structures of oxidized PVA hydrolase (OPH) from two known PVA-degrading organisms, Sphingopyxis sp. 113P3 and Pseudomonas sp. VM15C, including complexes with substrate analogues, acetylacetone and caprylate. The active site is covered by a lid-like beta-ribbon. Unlike other esterase and amidase, OPH is unique in cleaving the CC bond of beta-diketone, although it has a catalytic triad similar to that of most alpha/beta-hydrolases. Analysis of the crystal structures suggests a double-oxyanion-hole mechanism, previously only found in thiolase cleaving beta-ketoacyl-CoA. Three mutations in the lid region showed enhanced activity, with potential in industrial applications.
Title: The gene pvaB encodes oxidized polyvinyl alcohol hydrolase of Pseudomonas sp. strain VM15C and forms an operon with the polyvinyl alcohol dehydrogenase gene pvaA Shimao M, Tamogami T, Kishida S, Harayama S Ref: Microbiology, 146 ( Pt 3):649, 2000 : PubMed
A 5.7 kbp SphI fragment containing the polyvinyl alcohol (PVA) dehydrogenase gene pvaA and its 1.9 kbp 5'-flanking region was cloned from the PVA-degrading bacterium Pseudomonas sp. VM15C. The pvaB gene, encoding oxidized PVA hydrolase, was found in the region upstream of pvaA. Sequence data and expression studies indicated that pvaA and B constitute an operon in the order pvaBA. The pvaB gene encoded a protein of 379 amino acid residues (40610 Da), and a lipoprotein signal sequence and the lipase consensus sequence, Gly-X-Ser-X-Gly, characteristic of the active-site serine region in serine hydrolases, were detected in the deduced amino acid sequence. The pvaB product with the pvaA product constituted an enzyme system for the cleavage of PVA molecules. The pvaA product introduced beta-diketone groups into the PVA molecule, and the pvaB product hydrolysed these beta-diketone groups in oxidized PVA. The pvaB product also hydrolysed 4,6-nonanedione at a low rate, but not acetylacetone or 5-nonanone. It was completely inhibited by PMSF and was concluded to be a serine hydrolase. There were no proteins showing high similarity to the pvaB product in the databases, but minor similarity to a number of serine hydrolases including polyhydroxyalkanoate depolymerases was apparent.
Pseudomonas sp. pvaB. oxidized polyvinyl alcohol hydrolase precursor
