Linked Life Data

16615077

Source:http://linkedlifedata.com/resource/pubmed/id/16615077

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2006-4-19
pubmed:databankReference
pubmed:abstractText
Thymidylate synthase (TS) catalyzes the folate-dependent methylation of deoxyuridine monophosphate (dUMP) to form thymidine monophosphate (dTMP). We have investigated the role of invariant arginine 166, one of four arginines that contact the dUMP phosphate, using site-directed mutagenesis, X-ray crystallography, and TS from Escherichia coli. The R166Q mutant was crystallized in the presence of dUMP and a structure determined to 2.9 A resolution, but neither the ligand nor the sulfate from the crystallization buffer was found in the active site. A second structure determined with crystals prepared in the presence of dUMP and the antifolate 10-propargyl-5,8-dideazafolate revealed that the inhibitor was bound in an extended, nonproductive conformation, partially occupying the nucleotide-binding site. A sulfate ion, rather than dUMP, was found in the nucleotide phosphate-binding site. Previous studies have shown that the substitution at three of the four arginines of the dUMP phosphate-binding site is permissive; however; for Arg166, all the mutations lead to a near-inactive mutant. The present structures of TS R166Q reveal that the phosphate-binding site is largely intact, but with a substantially reduced affinity for phosphate, despite the presence of the three remaining arginines. The position of Cys146, which initiates catalysis, is shifted in the mutant and resides in a position that interferes with the binding of the dUMP pyrimidine moiety.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1095-6670
pubmed:author
pubmed:copyrightInfo
(c) 2006 Wiley Periodicals, Inc.
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
88-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16615077-Amino Acid Substitution, pubmed-meshheading:16615077-Arginine, pubmed-meshheading:16615077-Binding Sites, pubmed-meshheading:16615077-Catalysis, pubmed-meshheading:16615077-Crystallization, pubmed-meshheading:16615077-Crystallography, X-Ray, pubmed-meshheading:16615077-Deoxyuracil Nucleotides, pubmed-meshheading:16615077-Dimerization, pubmed-meshheading:16615077-Escherichia coli, pubmed-meshheading:16615077-Folic Acid, pubmed-meshheading:16615077-Folic Acid Antagonists, pubmed-meshheading:16615077-Hydrogen Bonding, pubmed-meshheading:16615077-Kinetics, pubmed-meshheading:16615077-Ligands, pubmed-meshheading:16615077-Models, Molecular, pubmed-meshheading:16615077-Molecular Structure, pubmed-meshheading:16615077-Protein Binding, pubmed-meshheading:16615077-Protein Conformation, pubmed-meshheading:16615077-Recombinant Proteins, pubmed-meshheading:16615077-Thymidine Monophosphate, pubmed-meshheading:16615077-Thymidylate Synthase
pubmed:year
2006
pubmed:articleTitle
Crystal structures of thymidylate synthase mutant R166Q: structural basis for the nearly complete loss of catalytic activity.
pubmed:affiliation
Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ 85721, USA. rrs@cascabel.ciad.mx
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't