Linked Life Data

14871895

Source:http://linkedlifedata.com/resource/pubmed/id/14871895

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2004-5-4
pubmed:databankReference
pubmed:abstractText
Oxalate decarboxylase (EC 4.1.1.2) catalyzes the conversion of oxalate to formate and carbon dioxide and utilizes dioxygen as a cofactor. By contrast, the evolutionarily related oxalate oxidase (EC 1.2.3.4) converts oxalate and dioxygen to carbon dioxide and hydrogen peroxide. Divergent free radical catalytic mechanisms have been proposed for these enzymes that involve the requirement of an active site proton donor in the decarboxylase but not the oxidase reaction. The oxidase possesses only one domain and manganese binding site per subunit, while the decarboxylase has two domains and two manganese sites per subunit. A structure of the decarboxylase together with a limited mutagenesis study has recently been interpreted as evidence that the C-terminal domain manganese binding site (site 2) is the catalytic site and that Glu-333 is the crucial proton donor (Anand, R., Dorrestein, P. C., Kinsland, C., Begley, T. P., and Ealick, S. E. (2002) Biochemistry 41, 7659-7669). The N-terminal binding site (site 1) of this structure is solvent-exposed (open) and lacks a suitable proton donor for the decarboxylase reaction. We report a new structure of the decarboxylase that shows a loop containing a 3(10) helix near site 1 in an alternative conformation. This loop adopts a "closed" conformation forming a lid covering the entrance to site 1. This conformational change brings Glu-162 close to the manganese ion, making it a new candidate for the crucial proton donor. Site-directed mutagenesis of equivalent residues in each domain provides evidence that Glu-162 performs this vital role and that the N-terminal domain is either the sole or the dominant catalytically active domain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19867-74
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:14871895-Bacillus subtilis, pubmed-meshheading:14871895-Binding Sites, pubmed-meshheading:14871895-Carbon Dioxide, pubmed-meshheading:14871895-Carboxy-Lyases, pubmed-meshheading:14871895-Catalysis, pubmed-meshheading:14871895-Catalytic Domain, pubmed-meshheading:14871895-Crystallography, X-Ray, pubmed-meshheading:14871895-Free Radicals, pubmed-meshheading:14871895-Glutamic Acid, pubmed-meshheading:14871895-Hydrogen Peroxide, pubmed-meshheading:14871895-Kinetics, pubmed-meshheading:14871895-Manganese, pubmed-meshheading:14871895-Models, Chemical, pubmed-meshheading:14871895-Models, Molecular, pubmed-meshheading:14871895-Mutagenesis, Site-Directed, pubmed-meshheading:14871895-Mutation, pubmed-meshheading:14871895-Oxidoreductases, pubmed-meshheading:14871895-Oxygen, pubmed-meshheading:14871895-Protein Conformation, pubmed-meshheading:14871895-Protein Structure, Tertiary, pubmed-meshheading:14871895-Protons, pubmed-meshheading:14871895-Solvents
pubmed:year
2004
pubmed:articleTitle
A closed conformation of Bacillus subtilis oxalate decarboxylase OxdC provides evidence for the true identity of the active site.
pubmed:affiliation
Biological Chemistry Department, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't