1e26 | pdb_00001e26

Design, Synthesis and X-ray Crystal Structure of a Potent Dual Inhibitor of Thymidylate Synthase and Dihydrofolate Reductase as an Antitumor Agent.

spinqualitylabelsall models 1e26, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1e26 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: GPB, NAP Related: 2cd2, 3cd2, 4cd2, 1dyr, 1daj Gene: C-DNA P.CARINII DHFR (PNECA) 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 from two independent crystal forms (P212121 and P21) of the folate (FA) binary complex and from the ternary complex with the oxidized coenzyme, NADP+, and recombinant Pneumocystis carinii dihydrofolate reductase (pcDHFR) refined to an average of 2.15 A resolution, show the first evidence of ligand-induced conformational changes in the structure of pcDHFR. These data are also compared with the crystal structure of the ternary complex of methotrexate (MTX) with NADPH and pcDHFR in the monoclinic lattice with data to 2.5 A resolution. Comparison of the data for the FA binary complex of pcDHFR with those for the ternary structures reveals significant differences, with a >7 A movement of the loop region near residue 23 that results in a new "flap-open" position for the binary complex, and a "closed" position in the ternary complexes, similar to that reported for Escherichia coli (ec) DHFR complexes. In the orthorhombic lattice for the binary FA pcDHFR complex, there is also an unwinding of a short helical region near residue 47 that places hydrophobic residues Phe-46 and Phe-49 toward the outer surface, a conformation that is stabilized by intermolecular packing contacts. The pyrophosphate moiety of NADP+ in the ternary folate pcDHFR complexes shows significant differences in conformation compared with that observed in the MTX-NADPH-pcDHFR ternary complex. Additionally, comparison of the conformations among these four pcDHFR structures reveals evidence for subdomain movement that correlates with cofactor binding states. The larger binding site access in the new "flap-open" loop 23 conformation of the binary FA complex is consistent with the rapid release of cofactor from the product complex during catalysis as well as the more rapid release of substrate product from the binary complex as a result of the weaker contacts of the closed loop 23 conformation, compared to ecDHFR. Ligand-induced conformational changes in the crystal structures of Pneumocystis carinii dihydrofolate reductase complexes with folate and NADP+.,Cody V, Galitsky N, Rak D, Luft JR, Pangborn W, Queener SF Biochemistry. 1999 Apr 6;38(14):4303-12. PMID:10194348 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dihydrofolate reductase

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