Rational design, synthesis, evaluation, and crystal structure of a potent inhibitor of human GAR Tfase: 10-(trifluoroacetyl)-5,10-dideazaacyclic-5,6,7,8-tetrahydrofolic acid
Autor: | Lata T. Gooljarsingh, Michael P. Hedrick, Stephen J. Benkovic, Joel Desharnais, Dale L. Boger, Arthur J. Olson, Thomas H. Marsilje, Ian A. Wilson, Chenglong Li, Ali Tavassoli, Yan Zhang |
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Rok vydání: | 2003 |
Předmět: |
Phosphoribosylglycinamide formyltransferase
Hydroxymethyl and Formyl Transferases Models Molecular Stereochemistry Macromolecular Substances Protein Conformation Static Electricity In Vitro Techniques Crystallography X-Ray Biochemistry Cofactor Cell Line chemistry.chemical_compound Escherichia coli Transferase Humans Tetrahydrofolic acid Enzyme Inhibitors Nuclear Magnetic Resonance Biomolecular Tetrahydrofolates Phosphoribosylglycinamide Formyltransferase chemistry.chemical_classification Binding Sites biology Rational design Recombinant Proteins Kinetics Enzyme chemistry Docking (molecular) Lometrexol Drug Design biology.protein |
Zdroj: | Biochemistry. 42(20) |
ISSN: | 0006-2960 |
Popis: | Glycinamide ribonucleotide transformylase (GAR Tfase) has been the target of anti-neoplastic intervention for almost two decades. Here, we use a structure-based approach to design a novel folate analogue, 10-(trifluoroacetyl)-5,10-dideazaacyclic-5,6,7,8-tetrahydrofolic acid (10-CF(3)CO-DDACTHF, 1), which specifically inhibits recombinant human GAR Tfase (K(i) = 15 nM), but is inactive (K(i) > 100 microM) against other folate-dependent enzymes that have been examined. Moreover, compound 1 is a potent inhibitor of tumor cell proliferation (IC(50) = 16 nM, CCRF-CEM), which represents a 10-fold improvement over Lometrexol, a GAR Tfase inhibitor that has been in clinical trials. Thus, this folate analogue 1 is among the most potent and selective inhibitors known toward GAR Tfase. Contributing to its efficacious activity, compound 1 is effectively transported into the cell by the reduced folate carrier and intracellularly sequestered by polyglutamation. The crystal structure of human GAR Tfase with folate analogue 1 at 1.98 A resolution represents the first structure of any GAR Tfase to be determined with a cofactor or cofactor analogue without the presence of substrate. The folate-binding loop of residues 141-146, which is highly flexible in both Escherichia coli and unliganded human GAR Tfase structures, becomes highly ordered upon binding 1 in the folate-binding site. Computational docking of the natural cofactor into this and other apo or complexed structures provides a rational basis for modeling how the natural cofactor 10-formyltetrahydrofolic acid interacts with GAR Tfase, and suggests that this folate analogue-bound conformation represents the best template to date for inhibitor design. |
Databáze: | OpenAIRE |
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