YcaO is an ATP- an Mg2+-binding protein involved in the peptidic biosynthesis of azoline. There three motifs involved in the binding are, in UniProtKB:P75838, 71-79: Sx3ExxER, 184-203: Sx6Ex3Qx3ExxER, and 286-290: RxxxE. Three slightly different functional families are represented in this family, proteins involved in TOMM (thiazole/oxazole-modified microcin) biogenesis, non-TOMM proteins such as UniProtKB:P75838, and TfuA-associated non-TOMM proteins involved in trifolitoxin biosynthesis. UniProtKB:P75838 hydrolyses ATP to AMP and pyrophosphate [1].

1: Discovery of a new ATP-binding motif involved in peptidic azoline biosynthesis. Dunbar KL, Chekan JR, Cox CL, Burkhart BJ, Nair SK, Mitchell DA; Nat Chem Biol. 2014;10:823-829. PMID:25129028