Type 1 glutamine amidotransferase (GATase1)-like domain found in proteins similar to Escherichia coli Hsp31 protein
Type 1 glutamine amidotransferase (GATase1)-like domain found in proteins similar to Escherichia coli Hsp31 protein (EcHsp31). This group includes EcHsp31 and Saccharomyces cerevisiae Ydr533c protein. EcHsp31 has chaperone activity. Ydr533c is upregulated in response to various stress conditions along with the heat shock family. EcHsp31 coordinates a metal ion using a 2-His-1-carboxylate motif present in various ions that use iron as a cofactor such as Carboxypeptidase A. The catalytic triad typical of GATase1 domains is not conserved in this GATase1-like domain. However, in common with a typical GATase1 domain, a reactive Cys residue is found in the sharp turn between a beta strand and an alpha helix termed the nucleophile elbow. For EcHsp31, this Cys together with a different His and, an Asp (rather than a Glu) residue form a different catalytic triad from the typical GATase1 domain. For Ydr533c a catalytic triad forms from the conserved Cys together with a different His and Glu from that of the typical GATase1domain. Ydr533c protein and EcHsp31 are homodimers.