1p4r
From Proteopedia
Crystal Structure of Human ATIC in complex with folate-based inhibitor BW1540U88UD
Structural highlights
Disease[PUR9_HUMAN] Defects in ATIC are the cause of AICAR transformylase/IMP cyclohydrolase deficiency (AICAR) [MIM:608688]. A neurologically devastating inborn error of purine biosynthesis. Patients excrete massive amounts of AICA-riboside in the urine and accumulate AICA-ribotide and its derivatives in erythrocytes and fibroblasts. AICAR causes profound mental retardation, epilepsy, dysmorphic features and congenital blindness.[1] [2] Function[PUR9_HUMAN] Bifunctional enzyme that catalyzes 2 steps in purine biosynthesis.[3] 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 PubMedAminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/IMP cyclohydrolase (ATIC) is a bifunctional enzyme with folate-dependent AICAR transformylase and IMP cyclohydrolase activities that catalyzes the last two steps of purine biosynthesis. The AICAR transformylase inhibitors BW1540 and BW2315 are sulfamido-bridged 5,8-dideazafolate analogs with remarkably potent K(i) values of 8 and 6 nm, respectively, compared with most other antifolates. Crystal structures of ATIC at 2.55 and 2.60 A with each inhibitor, in the presence of substrate AICAR, revealed that the sulfonyl groups dominate inhibitor binding and orientation through interaction with the proposed oxyanion hole. These agents then appear to mimic the anionic transition state and now implicate Asn(431') in the reaction mechanism along with previously identified key catalytic residues Lys(266) and His(267). Potent and selective inhibition of the AICAR transformylase active site, compared with other folate-dependent enzymes, should therefore be pursued by further design of sulfonyl-containing antifolates. Crystal structures of human bifunctional enzyme aminoimidazole-4-carboxamide ribonucleotide transformylase/IMP cyclohydrolase in complex with potent sulfonyl-containing antifolates.,Cheong CG, Wolan DW, Greasley SE, Horton PA, Beardsley GP, Wilson IA J Biol Chem. 2004 Apr 23;279(17):18034-45. Epub 2004 Feb 13. PMID:14966129[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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