Purine nucleotide-binding proteins build the large family of P-loop GTPases and related ATPases, which perform essential functions in all kingdoms of life. The Obg family comprises a group of ancient GTPases belonging to the TRAFAC (for translation factors) class. The Obg protein family is thought to comprise five ancient subfamilies, namely Obg/CgtA, YchF/YyaF, Drg/Rbg, Nog1, and Ygr210. Structural analysis of yeast and bacterial YchF revealed a modular organization formed by three domains, a central G domain, flanked by a coiled-coil domain and a TGS (ThrRS, GTPase, SpoT) domain PMID:17430889.

Only a few reports touch on the biological functions of YchF proteins and most focus on human and microorganisms. The YchF proteins may play a role in iron utilization and regulation of the Ton system in Brucella melitensis, and in the growth of the procyclic forms of Trypanosoma cruzi. The human YchF homolog hOLA1 suppresses cellular oxidative responses but enhances heat shock responses. In plants, we have shown that rice (OsYchF1) and Arabidopsis (AtYchF1) YchF proteins function as negative regulators in both abiotic stress responses and plant-defense responses PMID:26912459.

PMID:17430889 PMID:26912459