Structural Basis for the Inhibition of Human 5,10-Methenyltetrahydrofolate Synthetase by N10-Substituted Folate Analogues
5,10-Methenyltetrahydrofolate synthetase (MTHFS) regulates the flow of carbon through the one-carbon metabolic network,which supplies essential components for the growth and proliferation of cells. Inhibition of MTHFS in human MCF-7breast cancer cells has been shown to arrest the growth of cells. Absence of the three-dimensional structure of human MTHFS (hMTHFS) has hampered the rational design and optimization of drug candidates. Here, we report the structures of native hMTHFS, a binary complex of hMTHFS with ADP, hMTHFS bound with the N5-iminium phosphate reaction intermediate, and an enzyme-product complex of hMTHFS. The N5-iminium phosphate captured for the first time in our crystal structure unravels a unique strategy used by hMTHFS for recognition of the substrate and provides structural basis for the regulation of enzyme activity. Binding of NIO-substituted folate analogues places Y152 in the middle of the channel connecting ATP binding site with the substrate binding pocket, precluding the positioning of γ-phosphate for a nucleophilic attack. Using the structures of hMTHFS as a guide, we have probed the role of residues surrounding the active site in catalysis by mutagenesis. The ensemble of hMTHFS structures and the mutagenesis data yield a coherent picture of the MTHFS active site, determinants of substrate specificity, and new insights into the mechanism of inhibition of hMTHFS.
Dong Wu Yang Li Gaojie Song Chongyun Cheng Rongguang Zhang Andrzej Joachimiak Neil Shaw Zhi-Jie Liu
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beij Structural Biology Center, Argonne National Laboratory, Argonne, Illinois
国际会议
南京
英文
21-28
2009-09-11（万方平台首次上网日期，不代表论文的发表时间）