Dynamics of a Flexible Loop in Dihydrofolate Reductase from Escherichia coli and Its Implication for Catalysis

Christopher J. Falzone, Stephen Benkovic, Peter E. Wright

Research output: Contribution to journalArticle

140 Citations (Scopus)

Abstract

Apo-dihydrofolate reductase from Escherichia coli samples two distinct environments slowly on the NMR time scale at room temperature. Several assigned resonances belong to residues in, or proximal to, a loop (loop I) which is comprised of residues 9–24. This exchange process was altered (either removed or made fast on the NMR time scale) by deleting three hairpin turn forming residues from the loop and filling the gap with a single glycine [Li, L., Falzone, C. J., Wright, P. E., & Benkovic, S. J. (1992) Biochemistry 31, 7826–7833]. An approximate value of 35 s −1 for the exchange rate associated with loop I in apo-DHFR was obtained in two-dimensional nuclear Overhauser spectra by analyzing the time dependence of the cross-peak volume for ϵ H of Trp-22, a residue which is located in this loop and which has resolved cross-peaks. Owing to the critical role that this loop plays in catalysis, the correspondence between this rate of conformational exchange and off-rates for tetrahydrofolate and the reduced nicotinamide cofactor from product and substrate complexes suggests that loop movement may be a limiting factor in substrate turnover.

Original languageEnglish (US)
Pages (from-to)439-442
Number of pages4
JournalBiochemistry
Volume33
Issue number2
DOIs
StatePublished - Jan 1 1994

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Tetrahydrofolate Dehydrogenase
Catalysis
Escherichia coli
Nuclear magnetic resonance
Biochemistry
Niacinamide
Substrates
Glycine
Temperature
5,6,7,8-tetrahydrofolic acid

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Falzone, Christopher J. ; Benkovic, Stephen ; Wright, Peter E. / Dynamics of a Flexible Loop in Dihydrofolate Reductase from Escherichia coli and Its Implication for Catalysis. In: Biochemistry. 1994 ; Vol. 33, No. 2. pp. 439-442.
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Dynamics of a Flexible Loop in Dihydrofolate Reductase from Escherichia coli and Its Implication for Catalysis. / Falzone, Christopher J.; Benkovic, Stephen; Wright, Peter E.

In: Biochemistry, Vol. 33, No. 2, 01.01.1994, p. 439-442.

Research output: Contribution to journalArticle

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