3HXT

Structure of human MTHFS

Summary for 3HXT

• Entry DOI: 10.2210/pdb3hxt/pdb
• Related: 3HY3 3HY4 3HY6
• Descriptor: 5-formyltetrahydrofolate cyclo-ligase, NICKEL (II) ION, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: antifolate, cancer, one-carbon metabolic network, acetylation, atp-binding, cytoplasm, folate-binding, ligase, magnesium, nucleotide-binding, polymorphism
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P49914
• Total number of polymer chains: 1
• Total formula weight: 23694.60

Authors

Wu, D.,Li, Y.,Song, G.,Cheng, C.,Zhang, R.,Joachimiak, A.,Shaw, N.,Liu, Z.-J. (deposition date: 2009-06-22, release date: 2009-07-14, Last modification date: 2023-11-01)

Primary citation

Wu, D.,Li, Y.,Song, G.,Cheng, C.,Zhang, R.,Joachimiak, A.,Shaw, N.,Liu, Z.-J.
Structural basis for the inhibition of human 5,10-methenyltetrahydrofolate synthetase by N10-substituted folate analogues
Cancer Res., 69:7294-7301, 2009

PubMed Abstract: 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-7 breast 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 N10-substituted folate analogues places Y152 in the middle of the channel connecting ATP binding site with the substrate binding pocket, precluding the positioning of gamma-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.

PubMed: 19738041
DOI: 10.1158/0008-5472.CAN-09-1927

Experimental method

X-RAY DIFFRACTION (1.9 Å)