1jbv
FPGS-AMPPCP complexFPGS-AMPPCP complex
Structural highlights
FunctionFPGS_LACCA Involved in the conversion of folates to polyglutamate derivatives, and likely functions in the retention of cellular folate pools. Catalyzes successive MgATP-dependent additions of glutamate to a pteroylmonoglutamate substrate, with a high preference for 5,10-methylenetetrahydrofolate (mTHF). Thus, metabolizes mTHF to the tetraglutamate derivative, but longer glutamate chain length products are not observed. Tetrahydrofolate (H4PteGlu) and 10-formyl-H4PteGlu are poorer folate substrates. In contrast to E.coli FolC, this enzyme does not display dihydrofolate synthase activity.[1] [2] 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 PubMedFolic acid is an essential vitamin for normal cell growth, primarily through its central role in one-carbon metabolism. Folate analogs (antifolates) are targeted at the same reactions and are widely used as therapeutic drugs for cancer and bacterial infections. Effective retention of folates in cells and the efficacy of antifolate drugs both depend upon the addition of a polyglutamate tail to the folate or antifolate molecule by the enzyme folylpolyglutamate synthetase (FPGS). The reaction mechanism involves the ATP-dependent activation of the free carboxylate group on the folate molecule to give an acyl phosphate intermediate, followed by attack by the incoming L-glutamate substrate. FPGS shares a number of structural and mechanistic details with the bacterial cell wall ligases MurD, MurE and MurF, and these enzymes, along with FPGS, form a subfamily of the ADP-forming amide bond ligase family. High-resolution crystallographic analyses of binary and ternary complexes of Lactobacillus casei FPGS reveal that binding of the first substrate (ATP) is not sufficient to generate an active enzyme. However, binding of folate as the second substrate triggers a large conformational change that activates FPGS and allows the enzyme to adopt a form that is then able to bind the third substrate, L-glutamate, and effect the addition of a polyglutamate tail to the folate. Folate-binding triggers the activation of folylpolyglutamate synthetase.,Sun X, Cross JA, Bognar AL, Baker EN, Smith CA J Mol Biol. 2001 Jul 27;310(5):1067-78. PMID:11501996[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
| ||||||||||||||||||