1H, 15N and 13C resonance assignments of the S2A and H64A double mutant of human carbonic anhydrase II.

Abstract

Protein-water interactions profoundly influence protein structure and dynamics. Consequently, the function of many biomacromolecules is directly related to the presence and exchange of water molecules. While structural water molecules can be readily identified through X-ray crystallography, the dynamics within functional protein-water networks remain largely elusive. Therefore, to understand the role of biological water in protein dynamics and function, we have introduced S2A and H64A mutations in human Carbonic Anhydrase II (hCAII), a model system to study protein-water interactions. The mutations of serine to alanine at position 2 and histidine to alanine at position 64 cause an increase in hydrophobicity in the N-terminus and active site loop thereby restricting water entry and disrupting the water network in the Zn2+-binding pocket. To pave the way for a detailed investigation into the structural, functional, and mechanistic aspects of the Ser2Ala/His64Ala double mutant of hCAII, we present here almost complete sequence-specific resonance assignments for 1H, 15N, and 13C. These assignments serve as the basis for comprehensive studies on the dynamics of the protein-water network within the Zn2+-binding pocket and its role in catalysis.