Polyhydroxybutyrate (PHB) Synthases (PhaC): Toward understanding elongation granule formation and chain termination.
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چکیده
منابع مشابه
Chemistry with an Artificial Primer of Polyhydroxybutyrate Synthase Suggests a Mechanism for Chain Termination
Polyhydroxybutyrate (PHB) synthases (PhaCs) catalyze the conversion of 3-(R)-hydroxybutyryl CoA (HBCoA) to PHB, which is deposited as granules in the cytoplasm of microorganisms. The class I PhaC from Caulobacter crescentus (PhaC(Cc)) is a highly soluble protein with a turnover number of 75 s(-1) and no lag phase in coenzyme A (CoA) release. Studies with [1-(14)C]HBCoA and PhaC(Cc) monitored by...
متن کاملMechanistic Insight with HBCH[subscript 2]CoA as a Probe to Polyhydroxybutyrate (PHB) Synthases
Polyhydroxybutyrate (PHB) synthases catalyze the polymerization of 3-(R)-hydroxybutyrate coenzyme A (HBCoA) to produce polyoxoesters of 1−2 MDa. A substrate analogue HBCH2CoA, in which the S in HBCoA is replaced with a CH2 group, was synthesized in 13 steps using a chemoenzymatic approach in a 7.5% overall yield. Kinetic studies reveal it is a competitive inhibitor of a class I and a class III ...
متن کاملLipases provide a new mechanistic model for polyhydroxybutyrate (PHB) synthases: characterization of the functional residues in Chromatium vinosum PHB synthase.
Polyhydroxybutyrate (PHB) synthases catalyze the conversion of beta-hydroxybutyryl coenzyme A (HBCoA) to PHB. These enzymes require an active site cysteine nucleophile for covalent catalysis. A protein BLASTp search using the Class III Chromatium vinosum synthase sequence reveals high homology to prokaryotic lipases whose crystal structures are known. The homology is very convincing in the alph...
متن کاملMechanistic Insight with HBCH2CoA as a Probe to Polyhydroxybutyrate (PHB) Synthases
Polyhydroxybutyrate (PHB) synthases catalyze the polymerization of 3-(R)-hydroxybutyrate coenzyme A (HBCoA) to produce polyoxoesters of 1-2 MDa. A substrate analogue HBCH2CoA, in which the S in HBCoA is replaced with a CH2 group, was synthesized in 13 steps using a chemoenzymatic approach in a 7.5% overall yield. Kinetic studies reveal it is a competitive inhibitor of a class I and a class III ...
متن کاملPurification of polyhydroxybutyrate synthase from its native organism, Ralstonia eutropha: implications for the initiation and elongation of polymer formation in vivo.
Class I polyhydroxybutyrate (PHB) synthase (PhaC) from Ralstonia eutropha catalyzes the formation of PHB from (R)-3-hydroxybutyryl-CoA, ultimately resulting in the formation of insoluble granules. Previous mechanistic studies of R. eutropha PhaC, purified from Escherichia coli (PhaC(Ec)), demonstrated that the polymer elongation rate is much faster than the initiation rate. In an effort to iden...
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ژورنال
عنوان ژورنال: The FASEB Journal
سال: 2006
ISSN: 0892-6638,1530-6860
DOI: 10.1096/fasebj.20.5.a888-a