Crystal structures of Escherichia coli and Lactobacillus casei dihydrofolate reductase refined at 1.7 A resolution. I. General features and binding of methotrexate.
Bolin, J.T., Filman, D.J., Matthews, D.A., Hamlin, R.C., Kraut, J.(1982) J Biol Chem 257: 13650-13662
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- Primary Citation of Related Structures:  
3DFR, 4DFR - PubMed Abstract: 
- Effect of Single Amino Acid Replacements on the Folding and Stability of Dihydrofolate Reductase from Escherichia Coli
Perry, K.M., Onuffer, J.J., Touchette, N.A., Herndon, C.S., Gittelman, M.S., Matthews, C.R., Chen, J.-T., Mayer, R.J., Taira, K., Benkovic, S.J., Howell, E.E., Kraut, J.
(1987) Biochemistry 26: 2674 - Crystal Structures of Escherichia Coli and Lactobacillus Casei Dihydrofolate Reductase Refined at 1.7 Angstroms Resolution. II. Environment of Bound Nadph and Implications for Catalysis
Filman, D.J., Bolin, J.T., Matthews, D.A., Kraut, J.
(1982) J Biol Chem 257: 13663 - Crystal Structure of Avian Dihydrofolate Reductase Containing Phenyltriazine and Nadph
Volz, K.W., Matthews, D.A., Alden, R.A., Freer, S.T., Hansch, C., Kaufman, B.T., Kraut, J.
(1982) J Biol Chem 257: 2528 - Interpretation of Nuclear Magnetic Resonance Spectra for Lactobacillus Casei Dihydrofolate Reductase Based on the X-Ray Structure of the Enzyme-Methotrexate-Nadph Complex
Matthews, D.A.
(1979) Biochemistry 18: 1602 - Dihydrofolate Reductase from Lactobacillus Casei. Stereochemistry of Nadph Binding
Matthews, D.A., Alden, R.A., Freer, S.T., Xuong, N.-H., Kraut, J.
(1979) J Biol Chem 254: 4144 - Proton Magnetic Resonance Studies on Escherichia Coli Dihydrofolate Reductase. Assignment of Histidine C-2 Protons in Binary Complexes with Folates on the Basis of the Crystal Structure with Methotrexate and on Chemical Modifications
Poe, M., Hoogsteen, K., Matthews, D.A.
(1979) J Biol Chem 254: 8143 - Dihydrofolate Reductase from Lactobacillus Casei. X-Ray Structure of the Enzyme-Methotrexate-Nadph Complex
Matthews, D.A., Alden, R.A., Bolin, J.T., Filman, D.J., Freer, S.T., Hamlin, R., Hol, W.G.J., Kisliuk, R.L., Pastore, E.J., Plante, L.T., Xuong, N.-H., Kraut, J.
(1978) J Biol Chem 253: 6946 - Dihydrofolate Reductase. The Amino Acid Sequence of the Enzyme from a Methotrexate-Resistant Mutant of Escherichia Coli
Bennett, C.D., Rodkey, J.A., Sondey, J.M., Hirschmann, R.
(1978) Biochemistry 17: 1328 - Dihydrofolate Reductase. X-Ray Structure of the Binary Complex with Methotrexate
Matthews, D.A., Alden, R.A., Bolin, J.T., Freer, S.T., Hamlin, R., Xuong, N., Kraut, J., Poe, M., Williams, M., Hoogsteen, K.
(1977) Science 197: 452 - Dihydrofolate Reductase. Purification and Characterization of the Enzyme from an Amethopterin-Resistant Mutant of Escherichia Coli
Poe, M., Greenfield, N.J., Hirshfield, J.M., Williams, M.N., Hoogsteen, K.
(1972) Biochemistry 11: 1023
X-ray data have been extended to 1.7 A for a binary complex of Escherichia coli dihydrofolate reductase with methotrexate and a ternary complex of Lactobacillus casei dihydrofolate reductase with methotrexate and NADPH. Models for both structures have been refined to R factors of 0 ...
X-ray data have been extended to 1.7 A for a binary complex of Escherichia coli dihydrofolate reductase with methotrexate and a ternary complex of Lactobacillus casei dihydrofolate reductase with methotrexate and NADPH. Models for both structures have been refined to R factors of 0.15 and include parameters for fixed and liquid solvent. The two species of dihydrofolate reductase resemble one another even more closely than was thought to be the case prior to refinement. Several new structural features have also been discovered. Among them are a cis peptide linking Gly-97 and Gly-98 (L. Casei numbering) in both species, an alpha helix involving residues 43 through 50 in the E. coli enzyme, and the existence of what may be a specific hydration site on exposed alpha helices. Refinement has led to a revised description of the details of methotrexate binding. We now see that a fixed water molecule mediates the interaction between methotrexate's 2-amino group and Thr-116 (L. casei numbering) and that the inhibitor's 4-amino group makes two hydrogen bonds with the enzyme (instead of one). Other revisions are also discussed. A hypothetical model for substrate binding is proposed in which the pteridine ring is turned upside down while all protein and solvent atoms remain fixed. Asp-26 in this model is hydrogen bonded to the substrate's 2-amino group and to N3.
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Organizational Affiliation: 
School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, Australia.