Structural Basis for the Inhibition of Human 5,10-Methenyltetrahydrofolate Synthetase by N10-Substituted Folate Analogues
Published OnlineFirst September 8, 2009; DOI: 10.1158/0008-5472.CAN-09-1927 Experimental Therapeutics, Molecular Targets, and Chemical Biology Structural Basis for the Inhibition of Human 5,10-Methenyltetrahydrofolate Synthetase by N10-Substituted Folate Analogues Dong Wu,1 Yang Li,1 Gaojie Song,1 Chongyun Cheng,1 Rongguang Zhang,2 Andrzej Joachimiak,2 NeilShaw, 1 and Zhi-Jie Liu1 1National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China and 2Structural Biology Center, Argonne National Laboratory, Argonne, Illinois Abstract of the one-carbon metabolic network, dihydrofolate reductase, 5,10-Methenyltetrahydrofolate synthetase (MTHFS) regulates which catalyzes the conversion of dihydrofolate to tetrahydrofolate. the flow of carbon through the one-carbon metabolic network, Similarly, colorectal and pancreatic cancers are routinely treated by which supplies essential components for the growth and administration of the pyrimidine analogue 5-fluorouracil (5-FU), proliferation of cells. Inhibition of MTHFS in human MCF-7 which inhibits thymidylate synthase (TS; ref. 6). TS converts breast cancer cells has been shown to arrest the growth of deoxyuridylate to deoxythymidylate using a carbon donated by cells. Absence of the three-dimensional structure of human 5,10-methylenetetrahydrofolate (Fig. 1). This conversion is essential MTHFS (hMTHFS) has hampered the rational design and for DNA synthesis (7). To increase the clinical efficiency of the optimization of drug candidates. Here, we report the treatment, 5-formyltetrahydrofolate is often coadministered along structures of native hMTHFS, a binary complex of hMTHFS with 5-FU. The beneficial effect of administering 5-formyltetrahy- with ADP, hMTHFS bound with the N5-iminium phosphate drofolate during the therapy with 5-FU is a consequence of the reaction intermediate, and an enzyme-product complex of 5,10-methenyltetrahydrofolate synthetase (MTHFS)–catalyzed hMTHFS.
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