Polyhydroxyalkanoate synthases PhaC1 and PhaC2 from Pseudomonas stutzeri 1317 had different substrate specificities

The whole polyhydroxyalkanoate (PHA) synthesis gene locus of Pseudomonas stutzeri strain 1317 containing PHA synthase Genes phaC1(Ps), phaC2(Ps), and PHA depolymerase gene phaZ(Ps), was cloned using a PCR cloning strategy. The sequence analysis results of the phaC1(Ps), phaC2(Ps), and phaZ(Ps) showed high homology to the corresponding pha loci of the known Pseudomonas strains, respectively. PhaC1(Ps), and PhaC2(Ps) were functionally expressed in recombinant Escherichia coli strains and their substrate specificity was compared. The results demonstrated that PhaC1(Ps), and PhaC2(Ps) from P. stutzeri 1317 had different substrate specificities when expressed in E coli. In details, PhaC2(Ps), could incorporate both short-chain-length 3-hydroxybutyrate and medium-chain-length 3-hydroxyalkanoates (mcl 3HA) into PHA, while PhaCI(Ps), only favored mcl 3HA for polymerization. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Microbiological Societies.