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 language | English (US) |
|---|---|
| Pages (from-to) | 439-442 |
| Number of pages | 4 |
| Journal | Biochemistry |
| Volume | 33 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 1 1994 |
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All Science Journal Classification (ASJC) codes
- Biochemistry
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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 journal › Article
TY - JOUR
T1 - Dynamics of a Flexible Loop in Dihydrofolate Reductase from Escherichia coli and Its Implication for Catalysis
AU - Falzone, Christopher J.
AU - Benkovic, Stephen
AU - Wright, Peter E.
PY - 1994/1/1
Y1 - 1994/1/1
N2 - 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.
AB - 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.
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U2 - 10.1021/bi00168a007
DO - 10.1021/bi00168a007
M3 - Article
C2 - 8286374
AN - SCOPUS:0028049327
VL - 33
SP - 439
EP - 442
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 2
ER -