1s3y | pdb_00001s3y

Structure Determination of Tetrahydroquinazoline Antifolates in Complex with Human and Pneumocystis carinii Dihydrofolate Reductase: Correlations of Enzyme Selectivity and Stereochemistry

spinqualitylabelsall models 1s3y, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1s3y is a 1 chain structure with sequence from Pneca. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NAP, TQT Activity: Dihydrofolate reductase, with EC number 1.5.1.3 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DYR_PNECA] Key enzyme in folate metabolism. Catalyzes an essential reaction for de novo glycine and purine synthesis, and for DNA precursor synthesis. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Structural data are reported for the first examples of the tetrahydroquinazoline antifolate (6R,6S)-2,4-diamino-6-(1-indolinomethyl)-5,6,7,8-tetrahydroquinazoline (1) and its trimethoxy analogue (6R,6S)-2,4-diamino-6-(3',4',5'-trimethoxybenzyl)-5,6,7,8-tetrahydroquinaz oline (2) as inhibitor complexes with dihydrofolate reductase (DHFR) from human (hDHFR) and Pneumocystis carinii (pcDHFR) sources. The indoline analogue (1) was crystallized as ternary complexes with NADPH and hDHFR (1.9 A resolution) and pcDHFR (2.3 A resolution), while the trimethoxy quinazoline analogue (2) was crystallized as a binary complex with hDHFR in two polymorphic rhombohedral R3 lattices: R3(1) to 1.8 A resolution and R3(2) to 2.0 A resolution. Structural analysis of these potent and selective DHFR-inhibitor complexes revealed preferential binding of the 6S-equatorial isomer in each structure. This configuration is similar to that of the natural tetrahydrofolate substrate; that is, 6S. These data also show that in both the hDHFR and pcDHFR ternary complexes with (1) the indoline ring is partially disordered, with two static conformations that differ between structures. These conformers also differ from that observed for the trimethoxybenzyl ring of tetrahydroquinazoline (2). There is also a correlation between the disorder of the flexible loop 23 and the disorder of the cofactor nicotinamide ribose ring in the pcDHFR-NADPH-(1) ternary complex. Comparison of the Toxoplasma gondii DHFR (tgDHFR) sequence with those of other DHFRs provides insight into the role of sequence and conformation in inhibitor-binding preferences which may aid in the design of novel antifolates with specific DHFR selectivity. Structure determination of tetrahydroquinazoline antifolates in complex with human and Pneumocystis carinii dihydrofolate reductase: correlations between enzyme selectivity and stereochemistry.,Cody V, Luft JR, Pangborn W, Gangjee A, Queener SF Acta Crystallogr D Biol Crystallogr. 2004 Apr;60(Pt 4):646-55. Epub 2004, Mar 23. PMID:15039552 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dihydrofolate reductase 3D structures

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