Circularly permuted ATP-grasp prototyped by Roseiflexus RoseRS_2616 that is associated in gene neighborhoods with a GCS2-like COOH-NH2 ligase, alpha/beta hydrolase fold peptidase, GAT-II -like amidohydrolase, and M20 peptidase. Members of this family are predicted to be involved in the biosynthesis of small peptides [1].

1: Amidoligases with ATP-grasp, glutamine synthetase-like and acetyltransferase-like domains: synthesis of novel metabolites and peptide modifications of proteins. Iyer LM, Abhiman S, Maxwell Burroughs A, Aravind L; Mol Biosyst. 2009;5:1636-1660. PMID:20023723