Role of the Active-Site Carboxylate in Dihydrofolate Reductase: Kinetic and Spectroscopic Studies of the Aspartate 26 .fwdarw. Asparagine Mutant of the Lactobacillus casei Enzyme

Biochemistry ◽  
1995 ◽  
Vol 34 (9) ◽  
pp. 2872-2882 ◽  
Author(s):  
J. Basran ◽  
M. G. Casarotto ◽  
I. L. Barsukov ◽  
G. C. K. Roberts
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site ◽  
Lactobacillus Casei ◽  
Spectroscopic Studies

scholarly journals A 1H n.m.r. study of the role of the glutamate moiety in the binding of methotrexate to Lactobacillus casei dihydrofolate reductase

1984 ◽  
Vol 81 (2) ◽  
pp. 309-315 ◽  
Author(s):  
David J. Antonjuk ◽  
Berry Birdsall ◽  
H.T. Andrew Cheung ◽  
G. Marius Clore ◽  
James Feeney ◽  
...  
Keyword(s):  
Dihydrofolate Reductase ◽  
Lactobacillus Casei

Role of the conserved active site residue tryptophan-24 of human dihydrofolate reductase as revealed by mutagenesis

Biochemistry ◽  
1991 ◽  
Vol 30 (5) ◽  
pp. 1432-1440 ◽  
Author(s):  
William A. Beard ◽  
James R. Appleman ◽  
Shaoming Huang ◽  
Tavner J. Delcamp ◽  
James H. Freisheim ◽  
...  
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site ◽  
Active Site Residue ◽  
Human Dihydrofolate Reductase

Role of Active Site Loop Dynamics in Mediating Ligand Release from E. coli Dihydrofolate Reductase

Biochemistry ◽  
2021 ◽  
Author(s):  
Amrinder Singh ◽  
R. Bryn Fenwick ◽  
H. Jane Dyson ◽  
Peter E. Wright
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site ◽  
E Coli ◽  
Loop Dynamics

scholarly journals Computer modeling studies of the structural role of NADPH binding to active site mutants of human dihydrofolate reductase in complex with piritrexim.

2001 ◽  
Vol 48 (4) ◽  
pp. 903-916 ◽  
Author(s):  
W Nowak ◽  
V Cody ◽  
A Wojtczak
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site ◽  
Structural Changes ◽  
Energy Substitution ◽  
Energy Simulations ◽  
Detailed Computer ◽  
Human Dihydrofolate Reductase ◽  
Folate Cycle ◽  
Active Site Mutants

Dihydrofolate reductase (DHFR, EC 1.5.1.3) is one of the enzymes active in the folate cycle which plays an important role in DNA synthesis. Inhibition of DHFR is a key element in the treatment of many diseases, including cancer and AIDS related infections. A search for new selective inhibitors is motivated by the resistance to common drugs observed in the course of treatment. In this paper, results of a detailed computer analysis of human DHFR interactions with the lipophilic inhibitor piritrexim (PTX) are presented. It was found that the NADPH cofactor contributes 30% of the total PTX-enzyme interaction energy. Substitution of the highly conserved Glu30 with alanine does not lead to the release of the inhibitor from the hDHFR pocket. The important L22F point mutation does affect PTX orientation but does not changethe binding energy. Simulations of the dynamics of binary hDHFR-PTX complexes were performed with the use of Extensible Systematic Force Field (ESFF) and the results indicate structural changes in the enzyme induced by NADPH binding.

The use of triazine inhibitors in mapping the active site region of Lactobacillus casei dihydrofolate reductase

1979 ◽  
Vol 194 (2) ◽  
pp. 612-619 ◽  
Author(s):  
Stephen W. Dietrich ◽  
R.Nelson Smith ◽  
Sarah Brendler ◽  
Corwin Hansch
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site ◽  
Lactobacillus Casei ◽  
Active Site Region

scholarly journals Defining the role of active-site loop fluctuations in dihydrofolate reductase catalysis

2005 ◽  
Vol 102 (14) ◽  
pp. 5032-5037 ◽  
Author(s):  
D. McElheny ◽  
J. R. Schnell ◽  
J. C. Lansing ◽  
H. J. Dyson ◽  
P. E. Wright
Keyword(s):  
Dihydrofolate Reductase ◽  
Active Site

Probing the Role of an Active Site Aspartic Acid in Dihydrofolate Reductase

1997 ◽  
Vol 119 (35) ◽  
pp. 8166-8176 ◽  
Author(s):  
Vladimir A. Karginov ◽  
Sergey V. Mamaev ◽  
Haoyun An ◽  
Mark D. Van Cleve ◽  
Sidney M. Hecht ◽  
...  
Keyword(s):  
Aspartic Acid ◽  
Dihydrofolate Reductase ◽  
Active Site

scholarly journals Ultraviolet difference-spectroscopic studies of substrate and inhibitor binding to Lactobacillus casei dihydrofolate reductase

1978 ◽  
Vol 171 (2) ◽  
pp. 357-366 ◽  
Author(s):  
K Hood ◽  
G C K Roberts
Keyword(s):  
Dihydrofolate Reductase ◽  
Lactobacillus Casei ◽  
Ph Dependence ◽  
Difference Spectrum ◽  
Spectroscopic Studies ◽  
Tryptophan Residue ◽  
Difference Spectra ◽  
Inhibitor Binding ◽  
Independent Contribution ◽  
The Difference

The u.v. difference spectra generated when methotrexate, trimethoprim or folate bind to Lactobacillus casei dihydrofolate reductase were analysed. The difference spectrum producted by methotrexate binding is shown to consist of three components: (a) one closely resembling that observed on protonation of methotrexate, reflecting an increased degree of protonation on binding; (b) a pH-independent contribution corresponding to a 40 nm shift to longer wavelengths of a single absorption band of methotrexate: (c) a component arising from perturbation of tryptophan residue(s) of the enzyme. Quantitative analysis of the pH-dependence of component (a) shows that pK of methotrexate is increased from 5.35 to 8.55 (+/-0.10) on binding. In contrast, folate is not protonated when bound to the enzyme at neutral pH. At pH7.5, where methotrexate is bound 2000 times more tightly than folate, one-third of the difference in binding energy between the two compounds arises from the difference in chaarge stage. A similar analysis of the difference spectra generated on trimethoprim binding demonstrates that this compound, too, shows an increase in pK on binding but only from 7.22 to 7.90 (+/-0.10), suggesting that its 2,4-diaminopyrimidine ring does not bind to the enzyme in precisely the same way as the corresponding moiety of methotrexate.

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