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Computational characterization of the substrate-binding mode in coproporphyrinogen III oxidase

dc.contributor.authorSilva, Pedro J.
dc.contributor.authorRamos, Maria João
dc.date.accessioned2012-08-02T15:14:28Z
dc.date.available2012-08-02T15:14:28Z
dc.date.issued2011
dc.description.abstractOxygen-dependent coproporphyrinogen III oxidase catalyzes the sequential decarboxylation of the propionate substituents present on the A and B rings of coproporphyrinogen III in the heme biosynthetic pathway. Although extensive experimental investigation of this enzyme has already afforded many insights into its reaction mechanism, several key features (such as the substrate binding mode, the characterization of the active site, and the initial substrate protonation state) remain poorly described. The molecular dynamics simulations described in this paper enabled the determination of a very promising substrate binding mode and the extensive characterization of the enzyme active site. The proposed binding mode is fully consistent with the known selectivity of the active site toward substituted tetrapyrroles and explains the lack of activity of the H131A, R135A, D274A, and R275A mutants and the reasons behind the nonoccurrence of catalysis on the C and D rings of the tetrapyrrole. An important role in this binding mode is fulfilled by G276, as its carbonyl oxygen intervenes in the substrate anchoring by hydrogen bonding its ring D pyrrole NH group. The presence of this interaction (which is only possible with the protonated NH pyrrole group) and the absence of positively charged side chains close to the pyrrole nitrogen (which might stabilize the N-deprotonated pyrrole postulated in some mechanistic proposals) show that the pyrrole ring is very unlikely to undergo deprotonation during the catalytic cycle and allow the discrimination between the previously postulated mechanistic proposals.por
dc.identifier.citationSilva, Pedro J. e Ramos, Maria João (2011). Computational characterization of the substrate-binding mode in coproporphyrinogen III oxidase. Journal of Physical Chemistry B. Vol.115 (8), 1903-1910 DOI: 10.1021/jp110289d. ISSN 1520-6106.
dc.identifier.issn1520-6106
dc.identifier.urihttp://hdl.handle.net/10284/3295
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherAmerican Chemical Societypor
dc.relation.publisherversionThe definitive version is available at: http://pubs.acs.org/doi/abs/10.1021/jp110289d/ A versão definitiva está disponível em: http://pubs.acs.org/doi/abs/10.1021/jp110289dpor
dc.subjectMolecular dynamicspor
dc.subjectCoproporphyrinogen III oxidasepor
dc.subjectActive site characterizationpor
dc.titleComputational characterization of the substrate-binding mode in coproporphyrinogen III oxidasepor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage1910por
oaire.citation.issue8
oaire.citation.startPage1903por
oaire.citation.titleJournal of Physical Chemistry Bpor
oaire.citation.volume115
person.familyNameSilva
person.givenNamePedro
person.identifier.orcid0000-0001-9316-9275
person.identifier.scopus-author-id55310885700
rcaap.rightsopenAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublicationf4a9230e-0a0e-45b6-b894-e71ded186ef2
relation.isAuthorOfPublication.latestForDiscoveryf4a9230e-0a0e-45b6-b894-e71ded186ef2

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