Importance of a hydrophobic residue in binding and catalysis by dihydrofolate reductase

R. J. Mayer, J. T. Chen, K. Taira, C. A. Fierke, S. J. Benkovic

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

A conserved residue at the dihydrofolate binding site of dihydrofolate reductase (EC 1.5.1.3), leucine-54, was replaced with glycine to ascertain the role of this hydrophobic amino acid. The effect of the mutation is both to increase the dissociation rate of dihydrofolate and decrease the rate of hydride transfer thus changing the rate-limiting step in catalysis from product loss (leucine-54) to hydride transfer (glycine-54). The total stabilization by leucine-54 of the transition state for hydride transfer is ca. 104-fold (ΔΔG ~ 5.4 kcal/mol) at subsaturating dihydrofolate levels relative to free enzyme despite its location some 10 Å from the site of chemical reaction.

Original languageEnglish (US)
Pages (from-to)7718-7720
Number of pages3
JournalProceedings of the National Academy of Sciences of the United States of America
Volume83
Issue number20
DOIs
StatePublished - 1986

All Science Journal Classification (ASJC) codes

  • General

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