This family represents, additionally, the structurally related ATPase domains of histidine kinase, DNA gyrase B and HSP90.

1: Crystal structure of a novel non-Pfam protein AF1514 from Archeoglobus fulgidus DSM 4304 solved by S-SAD using a Cr X-ray source. Li Y, Bahti P, Shaw N, Song G, Chen S, Zhang X, Zhang M, Cheng C, Yin J, Zhu JY, Zhang H, Che D, Xu H, Abbas A, Wang BC, Liu ZJ; Proteins 2008;71:2109-13. PMID:18361456