Three-dimensional structure of a halotolerant algal carbonic anhydrase predicts halotolerance of a mammalian homolog.

ABSTRACT: Protein molecular adaptation to drastically shifting salinities was studied in dCA II, an alpha-type carbonic anhydrase (EC 4.2.1.1) from the exceptionally salt-tolerant unicellular green alga Dunaliella salina. The salt-inducible, extracellular dCA II is highly salt-tolerant and thus differs from its mesophilic homologs. The crystal structure of dCA II, determined at 1.86-A resolution, is globally similar to other alpha-type carbonic anhydrases except for two extended alpha-helices and an added Na-binding loop. Its unusual electrostatic properties include a uniformly negative surface electrostatic potential of lower magnitude than that observed in the highly acidic halophilic proteins and an exceptionally low positive potential at a site adjoining the catalytic Zn(2+) compared with mesoph

SUBMITTER: Premkumar L 

PROVIDER: S-EPMC1111892 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature