Effect of active-site mutation at Asn67 on the proton transfer mechanism of human carbonic anhydrase II.

ABSTRACT: The rate-limiting proton transfer (PT) event in the site-specific mutant N67L of human carbonic anhydrase II (HCA II) has been examined by kinetic, X-ray, and simulation approaches. The X-ray crystallography studies, which were previously reported, and molecular dynamics (MD) simulations indicate that the proton shuttling residue, His64, predominantly resides in the outward orientation with a significant disruption of the ordered water in the active site for the dehydration pathway. While disorder is seen in the active-site water, water cluster analysis indicates that the N67L mutant may form water clusters similar to those seen in the wild-type (WT). For the hydration pathway of the enzyme, the active site water cluster analysis reveals an inability of the N67L mutant to stabilize water c

SUBMITTER: Maupin CM 

PROVIDER: S-EPMC2739621 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature