1BZF

NMR SOLUTION STRUCTURE AND DYNAMICS OF THE COMPLEX OF LACTOBACILLUS CASEI DIHYDROFOLATE REDUCTASE WITH THE NEW LIPOPHILIC ANTIFOLATE DRUG TRIMETREXATE, 22 STRUCTURES

Summary for 1BZF

• Entry DOI: 10.2210/pdb1bzf/pdb
• NMR Information: BMRB: 4262
• Descriptor: DIHYDROFOLATE REDUCTASE, TRIMETREXATE (2 entities in total)
• Functional Keywords: oxidoreductase, inhibitor-enzyme complex
• Biological source: Lactobacillus casei
• Total number of polymer chains: 1
• Total formula weight: 18702.02

Authors

Polshakov, V.I.,Birdsall, B.,Frenkiel, T.A.,Gargaro, A.R.,Feeney, J. (deposition date: 1998-10-28, release date: 1999-05-18, Last modification date: 2024-05-22)

Primary citation

Polshakov, V.I.,Birdsall, B.,Frenkiel, T.A.,Gargaro, A.R.,Feeney, J.
Structure and dynamics in solution of the complex of Lactobacillus casei dihydrofolate reductase with the new lipophilic antifolate drug trimetrexate.
Protein Sci., 8:467-481, 1999

PubMed Abstract: We have determined the three-dimensional solution structure of the complex of Lactobacillus casei dihydrofolate reductase and the anticancer drug trimetrexate. Two thousand seventy distance, 345 dihedral angle, and 144 hydrogen bond restraints were obtained from analysis of multidimensional NMR spectra recorded for complexes containing 15N-labeled protein. Simulated annealing calculations produced a family of 22 structures fully consistent with the constraints. Several intermolecular protein-ligand NOEs were obtained by using a novel approach monitoring temperature effects of NOE signals resulting from dynamic processes in the bound ligand. At low temperature (5 degrees C) the trimethoxy ring of bound trimetrexate is flipping sufficiently slowly to give narrow signals in slow exchange, which give good NOE cross peaks. At higher temperature these broaden and their NOE cross peaks disappear thus allowing the signals in the lower-temperature spectrum to be identified as NOEs involving ligand protons. The binding site for trimetrexate is well defined and this was compared with the binding sites in related complexes formed with methotrexate and trimethoprim. No major conformational differences were detected between the different complexes. The 2,4-diaminopyrimidine-containing moieties in the three drugs bind essentially in the same binding pocket and the remaining parts of their molecules adapt their conformations such that they can make effective van der Waals interactions with essentially the same set of hydrophobic amino acids, the side-chain orientations and local conformations of which are not greatly changed in the different complexes (similar chi1 and chi2 values).

PubMed: 10091649

Experimental method

SOLUTION NMR