Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
1991-1-15
pubmed:abstractText
The 2.3-A crystal structure of recombinant human dihydrofolate reductase (EC 1.5.1.3, DHFR) has been solved as a binary complex with folate (a poor substrate at neutral pH) and also as a binary complex with an inhibitor, 5-deazafolate. The inhibitor appears to be protonated at N8 on binding, whereas folate is not. Rotation of the peptide plane joining I7 and V8 from its position in the folate complex permits hydrogen bonding of 5-deazafolate's protonated N8 to the backbone carbonyl of I7, thus contributing to the enzyme's greater affinity for 5-deazafolate than for folate. In this respect it is likely that bound 5-deazafolate furnishes a model for 7,8-dihydrofolate binding and, in addition, resembles the transition state for folate reduction. A hypothetical transition-state model for folate reduction, generated by superposition of the DHFR binary complexes human.5-deazafolate and chicken liver.NADPH, reveals a 1-A overlap of the binding sites for folate's pteridine ring and the dihydronicotinamide ring of NADPH. It is proposed that this binding-site overlap accelerates the reduction of both folate and 7,8-dihydrofolate by simultaneously binding substrate and cofactor with a sub van der Waals separation that is optimal for hydride transfer.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9467-79
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Crystal structures of recombinant human dihydrofolate reductase complexed with folate and 5-deazafolate.
pubmed:affiliation
Department of Chemistry, University of California, San Diego, La Jolla 92093.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't