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dc.contributor.authorChen, Chao
dc.contributor.authorCao, Ruikai
dc.contributor.authorShrestha, Ruben
dc.contributor.authorWard, Christina
dc.contributor.authorKatz, Benjamin B.
dc.contributor.authorFischer, Christopher J.
dc.contributor.authorTomich, John M.
dc.contributor.authorLi, Ping
dc.identifier.citationChen, Chao et al. “Trapping of Intermediates with Substrate Analog HBOCoA in the Polymerizations Catalyzed by Class III Polyhydroxybutyrate (PHB) Synthase from Allochromatium Vinosum.” ACS chemical biology 10.5 (2015): 1330–1339. PMC. Web. 15 July 2016.en_US
dc.description.abstractPolyhydroxybutyrate (PHB) synthases (PhaCs) catalyze the formation of biodegradable PHB polymers that are considered as an ideal alternative to petroleum-based plastics. To provide strong evidence for the preferred mechanistic model involving covalent and noncovalent intermediates, a substrate analog HBOCoA was synthesized chemoenzymatically. Substitution of sulfur in the native substrate HBCoA with an oxygen in HBOCoA enabled detection of (HB)nOCoA (n = 2–6) intermediates when the polymerization was catalyzed by wild-type (wt-)PhaECAv at 5.84 hr−1. This extremely slow rate is due to thermodynamically unfavorable steps that involve formation of enzyme-bound PHB species (thioesters) from corresponding CoA oxoesters. Synthesized standards (HB)nOCoA (n = 2–3) were found to undergo both reacylation and hydrolysis catalyzed by the synthase. Distribution of the hydrolysis products highlights the importance of the penultimate ester group as previously suggested. Importantly, the reaction between primed synthase [3H]-sT-PhaECAv and HBOCoA yielded [3H]-sTet-O-CoA at a rate constant faster than 17.4 s−1, which represents the first example that a substrate analog undergoes PHB chain elongation at a rate close to that of the native substrate (65.0 s−1). Therefore, for the first time with a wt-synthase, strong evidence was obtained to support our favored PHB chain elongation model.en_US
dc.publisherAmerican Chemical Societyen_US
dc.titleTrapping of Intermediates with Substrate Analog HBOCaA in the Polymerizations Catalyzer by Class III Polyhydroxybutyrate (PHB) Synthase from Allochromatium Vinosumen_US
kusw.kuauthorFischer, Christopher J.
kusw.kudepartmentPhysics and Astronomyen_US
kusw.oanotesPer SHERPA/RoMEO 7/15/2016: Author's Pre-print: grey tick subject to Restrictions below, author can archive pre-print (ie pre-refereeing) Restrictions:

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kusw.oaversionScholarly/refereed, author accepted manuscripten_US
kusw.oapolicyThis item meets KU Open Access policy criteria.en_US

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