Characterization of a GlgC homolog from extremely halophilic archaeon Haloarcula japonica.

Glycogen synthesis in bacteria is mainly organized by the products of glgB, glgC and glgA genes comprising the widely known glg operon. On the genome of extremely halophilic archaeon Haloarcula japonica, there was a gene cluster analogous to the bacterial glg operon. In this study, we focused on a GlgC homolog of Ha. japonica, and its recombinant enzyme was prepared and characterized. The enzyme showed highest activity toward GTP and glucose-1-phosphate (Glc-1-P) as substrates in the presence of 2.6 M KCl, and predicted to be work as "GDP-glucose pyrophosphorylase" in Ha. japonica.