Linked Life Data

20709352

Source:http://linkedlifedata.com/resource/pubmed/id/20709352

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2010-10-25
pubmed:abstractText
The tautomerase superfamily consists of structurally homologous proteins that are characterized by a ?-?-? fold and a catalytic amino-terminal proline. 4-Oxalocrotonate tautomerase (4-OT) family members have been identified and categorized into five subfamilies on the basis of multiple sequence alignments and the conservation of key catalytic and structural residues. Representative members from two subfamilies have been cloned, expressed, purified, and subjected to kinetic and structural characterization. The crystal structure of DmpI from Helicobacter pylori (HpDmpI), a 4-OT homolog in subfamily 3, has been determined to high resolution (1.8Å and 2.1Å) in two different space groups. HpDmpI is a homohexamer with an active site cavity that includes Pro-1, but lacks the equivalent of Arg-11 and Arg-39 found in 4-OT. Instead, the side chain of Lys-36 replaces that of Arg-11 in a manner similar to that observed in the trimeric macrophage migration inhibitory factor (MIF), which is the title protein of another family in the superfamily. The electrostatic surface of the active site is also quite different and suggests that HpDmpI might prefer small, monoacid substrates. A kinetic analysis of the enzyme is consistent with the structural analysis, but a biological role for the enzyme remains elusive. The crystal structure of DmpI from Archaeoglobus fulgidus (AfDmpI), a 4-OT homolog in subfamily-4, has been determined to 2.4Å resolution. AfDmpI is also a homohexamer, with a proposed active site cavity that includes Pro-1, but lacks any other residues that are readily identified as catalytic ones related to 4-OT activity. Indeed, the electrostatic potential of the active site differs significantly in that it is mostly neutral, in contrast to the usual electropositive features found in other 4-OT family members, suggesting that AfDmpI might accommodate hydrophobic substrates. A kinetic analysis has been carried out, but does not provide any clues about the type of reaction the enzyme might catalyze.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1090-2120
pubmed:author
pubmed:copyrightInfo
Copyright © 2010 Elsevier Inc. All rights reserved.
pubmed:issnType
Electronic
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
252-9
pubmed:dateRevised
2011-5-27
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Kinetic and structural characterization of DmpI from Helicobacter pylori and Archaeoglobus fulgidus, two 4-oxalocrotonate tautomerase family members.
pubmed:affiliation
The University of Texas, Austin, 78712-1071, United States.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural