Work

Phosphate Binding in PNP Alters Transition-State Analogue Affinity and Subunit Cooperativity

Year: 2023

Type: article

Abstract: Purine nucleoside phosphorylases (PNPs) catalyze the phosphorolysis of 6-oxypurine nucleosides with an HPO 4 2– dianion nucleophile. Nucleosides and phosphate occupy distinct pockets in the PNP active site. Evaluation of the HPO 4 2– site by mutagenesis, cooperative binding studies, and thermodynamic and structural analysis demonstrate that alterations in the HPO 4 2– 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 HPO 4 2– 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.

Source: Biochemistry

DOI: 10.1021/acs.biochem.3c00264

Authors: Yacoba V. T. Minnow, Vern L. Schramm, Steven C. Almo, Agnidipta Ghosh

Institution: Albert Einstein College of Medicine

Language: English

Topic: Biochemical and Molecular Research

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: National Institutes of Health, National Institute of General Medical Sciences, National Institute of Allergy and Infectious Diseases