Abstract
Purine nucleoside phosphorylases (PNPs) catalyze the phosphorolysis of 6-oxypurine nucleosides with an HPO42- dianion nucleophile. Nucleosides and phosphate occupy distinct pockets in the PNP active site. Evaluation of the HPO42- site by mutagenesis, cooperative binding studies, and thermodynamic and structural analysis demonstrate that alterations in the HPO42- binding site can render PNP inactive and significantly impact subunit cooperativity and binding to transition-state analogue inhibitors. Cooperative interactions between the cationic transition-state analogue and the anionic HPO42- nucleophile demonstrate the importance of reforming the transition-state ensemble for optimal inhibition with transition-state analogues. Altered phosphate binding in the catalytic site mutants helps to explain one of the known lethal PNP deficiency syndromes in humans.
Original language | English (US) |
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Pages (from-to) | 3116-3125 |
Number of pages | 10 |
Journal | Biochemistry |
Volume | 62 |
Issue number | 21 |
DOIs | |
State | Published - Nov 7 2023 |
ASJC Scopus subject areas
- Biochemistry