Crystal structure of TS-DHFR from Cryptosporidium hominis in complex with NADPH, FdUMP and 2-(2-(4-((2-amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-5-yl)methyl)benzamido)phenyl)acetic acid.
Cryptosporidiosis is a human gastrointestinal disease caused by protozoans of the genus Cryptosporidium, which can be fatal in immunocompromised individuals. The essential enzyme, thymidylate synthase (TS), is responsible for de novo synthesis of deoxythymidine monophosphate ...
Cryptosporidiosis is a human gastrointestinal disease caused by protozoans of the genus Cryptosporidium, which can be fatal in immunocompromised individuals. The essential enzyme, thymidylate synthase (TS), is responsible for de novo synthesis of deoxythymidine monophosphate. The TS active site is relatively conserved between Cryptosporidium and human enzymes. In previous work, we identified compound 1, (2-amino-4-oxo-4,7-dihydro-pyrrolo[2,3-d]pyrimidin-methyl-phenyl-l-glutamic acid), as a promising selective Cryptosporidium hominis TS (ChTS) inhibitor. In the present study, we explore the structure-activity relationship around 1 glutamate moiety by synthesizing and biochemically evaluating the inhibitory activity of analogues against ChTS and human TS (hTS). X-Ray crystal structures were obtained for compounds bound to both ChTS and hTS. We establish the importance of the 2-phenylacetic acid moiety methylene linker in optimally positioning compounds 23, 24, and 25 within the active site. Moreover, through the comparison of structural data for 5, 14, 15, and 23 bound in both ChTS and hTS identified that active site rigidity is a driving force in determining inhibitor selectivity.
Organizational Affiliation:
Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University, 225 Prospect Street, PO Box 208107, New Haven, CT, 06520, USA. Electronic address: karen.anderson@yale.edu.
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