Proton Occupancies in Histidine Side Chains of Carbonic Anhydrase II by Neutron Crystallography and NMR - Differences, Similarities and Opportunities.

ABSTRACT: Histidine is a key amino-acid residues in proteins that can exist in three different protonation states: two different neutral tautomeric forms and a protonated, positively charged one. It can act as both donor and acceptor of hydrogen bonds, coordinate metal ions, and engage in acid/base catalysis. Human Carbonic Anhydrase II (HCA II) is a pivotal enzyme catalyzing the reversible hydration of carbon dioxide. It contains 12 histidine residues: six are surface exposed, two buried, three are active site zinc ion ligands, and one is a proton shuttle. Comparing results from NMR spectroscopy with previously determined neutron protein crystal structures enabled a side-by-side investigation of the proton occupancies and preferred tautomeric states of the histidine residues in HCA II. Buried and z

SUBMITTER: Zoe Fisher S 

PROVIDER: S-EPMC11875562 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature