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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1988-2-17
|
| pubmed:abstractText |
The interaction of dihydrofolate reductase (DHFR) from Escherichia coli with drugs such as methotrexate (MTX) and 2,4-diamino-6,7-dimethylpteridine (DAM) has been studied by means of site-directed mutagenesis, fluorescence spectroscopy, and steady-state as well as transient kinetics. A strictly conserved residue at the dihydrofolate binding site of DHFR, phenylalanine-31, has been replaced with tyrosine or valine to ascertain the importance for binding of this hydrophobic amino acid, which interacts with both the pteridine ring and the p-aminobenzoyl moiety. The first mutation (Phe-31----Tyr) has a minimal effect on the binding of the classical inhibitor, DAM. On the other hand, the second mutation (Phe-31----Val) has increased the dissociation constant of DAM from the DHFR.NADPH.DAM ternary complex over 150-fold (greater than 3 kcal/mol). The dissociation constant of DAM from the (Val31-DHFR).DAM binary complex was too large to be measured fluorometrically. More importantly, these mutations have decreased the overall tight binding of MTX, from 100- to 140-fold (corresponding to a loss of binding energy of 2.2-2.4 kcal/mol) for the Tyr-31 and Val-31 mutants, respectively. These results indicate that hydrophobic interactions between MTX and DHFR are at least as important as formation of the MTX.DHFR salt bridge in the tight binding of MTX.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jan
|
| pubmed:issn |
0022-2623
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
31
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
129-37
|
| pubmed:dateRevised |
2000-12-18
|
| pubmed:meshHeading |
pubmed-meshheading:3275776-Binding Sites,
pubmed-meshheading:3275776-Escherichia coli,
pubmed-meshheading:3275776-Kinetics,
pubmed-meshheading:3275776-Mathematics,
pubmed-meshheading:3275776-Methotrexate,
pubmed-meshheading:3275776-Mutation,
pubmed-meshheading:3275776-Protein Binding,
pubmed-meshheading:3275776-Pteridines,
pubmed-meshheading:3275776-Spectrometry, Fluorescence,
pubmed-meshheading:3275776-Spectrophotometry,
pubmed-meshheading:3275776-Tetrahydrofolate Dehydrogenase,
pubmed-meshheading:3275776-Thermodynamics
|
| pubmed:year |
1988
|
| pubmed:articleTitle |
Evaluation of the importance of hydrophobic interactions in drug binding to dihydrofolate reductase.
|
| pubmed:affiliation |
Department of Chemistry, Pennsylvania State University, University Park 16802.
|
| pubmed:publicationType |
Journal Article
|