Open AccessDetermination of the active sites serine of the poly (3‐hydroxybutyrate) depolymerases of Pseudomonas lemoignei (PhaZ5) and of Alcaligenes faecalis
Author(s) -
Shinohe Takeyuki,
Nojiri Masaki,
Saito Terumi,
Stanislawski Thomas,
Jendrossek Dieter
Publication year - 1996
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1996.tb08370.x
Subject(s) - alcaligenes faecalis , serine , alcaligenes , pseudomonas , serine hydrolase , chemistry , biochemistry , mutant , lipase , bacteria , enterococcus faecalis , stereochemistry , enzyme , biology , escherichia coli , genetics , gene
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 S 138 ( P. lemoignei ) and S 139 ( 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 S 195 ( P. lemoignei ) and S 196 ( A. faecalis ), resulted in mutant proteinswith 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.