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Article: Structure and catalytic mechanism of the thioesterase CalE7 in enediyne biosynthesis

TitleStructure and catalytic mechanism of the thioesterase CalE7 in enediyne biosynthesis
Authors
Issue Date2009
PublisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/
Citation
Journal Of Biological Chemistry, 2009, v. 284 n. 23, p. 15739-15749 How to Cite?
AbstractThe biosynthesis of the enediyne moiety of the antitumor natural product calicheamicin involves an iterative polyketide synthase (CalE8) and other ancillary enzymes. In the proposed mechanism for the early stage of 10-membered enediyne biosynthesis, CalE8 produces a carbonyl-conjugated polyene with the assistance of a putative thioesterase (CalE7). We have determined the x-ray crystal structure of CalE7 and found that the subunit adopts a hotdog fold with an elongated and kinked substrate-binding channel embedded between two subunits. The 1.75-Å crystal structure revealed that CalE7 does not contain a critical catalytic residue (Glu or Asp) conserved in other hotdog fold thioesterases. Based on biochemical and site-directed mutagenesis studies, we proposed a catalytic mechanism in which the conserved Arg 37 plays a crucial role in the hydrolysis of the thioester bond, and that Tyr 29 and a hydrogen-bonded water network assist the decarboxylation of the β-ketocarboxylic acid intermediate. Moreover, computational docking suggested that the substrate-binding channel binds a polyene substrate that contains a single cis double bond at the C4/C5 position, raising the possibility that the C4=C5 double bond in the enediyne moiety could be generated by the iterative polyketide synthase. Together, the results revealed a hotdog fold thioesterase distinct from the common type I and type II thioesterases associated with polyketide biosynthesis and provided interesting insight into the enediyne biosynthetic mechanism. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.
Persistent Identifierhttp://hdl.handle.net/10722/171777
ISSN
2015 Impact Factor: 4.258
2015 SCImago Journal Rankings: 3.151
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorKotaka, Men_US
dc.contributor.authorKong, Ren_US
dc.contributor.authorQureshi, Ien_US
dc.contributor.authorHo, QSen_US
dc.contributor.authorSun, Hen_US
dc.contributor.authorLiew, CWen_US
dc.contributor.authorGoh, LPen_US
dc.contributor.authorCheung, Pen_US
dc.contributor.authorMu, Yen_US
dc.contributor.authorLescar, Jen_US
dc.contributor.authorLiang, ZXen_US
dc.date.accessioned2012-10-30T06:17:00Z-
dc.date.available2012-10-30T06:17:00Z-
dc.date.issued2009en_US
dc.identifier.citationJournal Of Biological Chemistry, 2009, v. 284 n. 23, p. 15739-15749en_US
dc.identifier.issn0021-9258en_US
dc.identifier.urihttp://hdl.handle.net/10722/171777-
dc.description.abstractThe biosynthesis of the enediyne moiety of the antitumor natural product calicheamicin involves an iterative polyketide synthase (CalE8) and other ancillary enzymes. In the proposed mechanism for the early stage of 10-membered enediyne biosynthesis, CalE8 produces a carbonyl-conjugated polyene with the assistance of a putative thioesterase (CalE7). We have determined the x-ray crystal structure of CalE7 and found that the subunit adopts a hotdog fold with an elongated and kinked substrate-binding channel embedded between two subunits. The 1.75-Å crystal structure revealed that CalE7 does not contain a critical catalytic residue (Glu or Asp) conserved in other hotdog fold thioesterases. Based on biochemical and site-directed mutagenesis studies, we proposed a catalytic mechanism in which the conserved Arg 37 plays a crucial role in the hydrolysis of the thioester bond, and that Tyr 29 and a hydrogen-bonded water network assist the decarboxylation of the β-ketocarboxylic acid intermediate. Moreover, computational docking suggested that the substrate-binding channel binds a polyene substrate that contains a single cis double bond at the C4/C5 position, raising the possibility that the C4=C5 double bond in the enediyne moiety could be generated by the iterative polyketide synthase. Together, the results revealed a hotdog fold thioesterase distinct from the common type I and type II thioesterases associated with polyketide biosynthesis and provided interesting insight into the enediyne biosynthetic mechanism. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.en_US
dc.languageengen_US
dc.publisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/en_US
dc.relation.ispartofJournal of Biological Chemistryen_US
dc.titleStructure and catalytic mechanism of the thioesterase CalE7 in enediyne biosynthesisen_US
dc.typeArticleen_US
dc.identifier.emailKotaka, M:masayo@hku.hken_US
dc.identifier.authorityKotaka, M=rp00293en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1074/jbc.M809669200en_US
dc.identifier.pmid19357082-
dc.identifier.scopuseid_2-s2.0-67650138601en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-67650138601&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume284en_US
dc.identifier.issue23en_US
dc.identifier.spage15739en_US
dc.identifier.epage15749en_US
dc.identifier.isiWOS:000266501000043-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridKotaka, M=6604073578en_US
dc.identifier.scopusauthoridKong, R=55107990500en_US
dc.identifier.scopusauthoridQureshi, I=14623211700en_US
dc.identifier.scopusauthoridHo, QS=24437293700en_US
dc.identifier.scopusauthoridSun, H=26968179900en_US
dc.identifier.scopusauthoridLiew, CW=24437011000en_US
dc.identifier.scopusauthoridGoh, LP=24436832800en_US
dc.identifier.scopusauthoridCheung, P=53263518400en_US
dc.identifier.scopusauthoridMu, Y=7103374032en_US
dc.identifier.scopusauthoridLescar, J=6603844493en_US
dc.identifier.scopusauthoridLiang, ZX=23668102800en_US

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