Comment | This subfamily belongs to bacterial extracellular solute-binding protein family 3 (PF00497). In that family, most members are ABC transporter periplasmic substrate-binding proteins. However, members of the present subfamily are orphans in the sense of being adjacent to neither ABC transporter ATP-binding proteins or permease subunits. Instead, most members are encoded next to the two signature proteins of the proposed Glycine-Rich Repeat Modification (GRRM) system, a radical SAM/SPASM protein GrrM (TIGR04261) and the Gly-rich repeat protein itself GrrA (TIGR04260). |