title: Alcoholytic cleavage of polyhydroxyalkanoate chains by class IV synthases induced by endogenous and exogenous ethanol.
abstract: Polyhydroxyalkanoate (PHA)-producing Bacillus strains express class IV PHA synthase, which is composed of the subunits PhaR and PhaC. Recombinant Escherichia coli expressing PHA synthase from Bacillus cereus strain YB-4 (PhaRCYB-4) showed an unusual reduction of the molecular weight of PHA produced during the stationary phase of growth. Nuclear magnetic resonance analysis of the low-molecular-weight PHA revealed that its carboxy end structure was capped by ethanol, suggesting that the molecular weight reduction was the result of alcoholytic cleavage of PHA chains by PhaRCYB-4 induced by endogenous ethanol. This scission reaction was also induced by exogenous ethanol in both in vivo and in vitro assays. In addition, PhaRCYB-4 was observed to have alcoholysis activity for PHA chains synthesized by other synthases. The PHA synthase from Bacillus megaterium (PhaRCBm) from another subgroup of class IV synthases was also assayed and was shown to have weak alcoholysis activity for PHA chains. These results suggest that class IV synthases may commonly share alcoholysis activity as an inherent feature.
authors: Department of Innovative and Engineered Materials, Tokyo Institute of Technology, Yokohama, Japan.
authors: Manami
authors: M
authors: Hyakutake
authors: Satoshi
authors: S
authors: Tomizawa
authors: Kouhei
authors: K
authors: Mizuno
authors: Hideki
authors: H
authors: Abe
authors: Takeharu
authors: T
authors: Tsuge
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001409:Bacillus cereus / Q000201:enzymology* / Q000235:genetics; D001410:Bacillus megaterium / Q000201:enzymology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D054813:Polyhydroxyalkanoates; D011994:Recombinant Proteins; D000431:Ethanol; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase