title: Determination of the active sites serine of the poly (3-hydroxybutyrate) depolymerases of Pseudomonas lemoignei (PhaZ5) and of Alcaligenes faecalis.
abstract: Mutational analysis of the poly(3-hydroxybutyrate) (PHB) depolymerase A of Pseudomonas lemoignei and of the poly(3-hydroxybutyrate) depolymerase of Alcaligenes faecalis revealed that S138 (P. lemoignei) and S139 (A. faecalis) are essential for activity. Both serines are part of a strictly conserved pentapeptide sequence which is present in all poly(3-hydroxybutyrate) depolymerases analyzed so far (G-L-S-S(A)-G) and which resembles the lipase box of lipases and other serine hydrolases (G-X-S-X-G). Mutation of another conserved serine, namely S195 (P. lemoignei) and S196 (A. faecalis), resulted in mutant proteins with almost full activity and proved that S195 and S196 are not essential for activity. The results indicate the structural and functional relationship of poly(3-hydroxybutyrate) depolymerases to the family of serine hydrolases.
authors.affiliation: Department of Biological Sciences, Kanagawa University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shinohe
authors.forename: M
authors.initials: M
authors.lastname: Nojiri
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Stanislawski
authors.forename: D
authors.initials: D
authors.lastname: Jendrossek
mesh_terms: D000421:Alcaligenes / Q000201:enzymology*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics; D007531:Isoflurophate / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D011549:Pseudomonas / Q000201:enzymology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D012694:Serine / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; D007531:Isoflurophate; D012694:Serine; D002265:Carboxylic Ester Hydrolases; C022417:poly-beta-hydroxybutyrate depolymerase