Curation Notes: ureG (C5CY05, Vapar_4248) in Variovorax paradoxus S110 (VARPS)

Summary

• Gene / Locus: ureG (Vapar_4248, UniProtKB C5CY05, Swiss-Prot reviewed, 216 aa).
• Domain Architecture & Active-Site Motifs: SIMIBI-class G3E GTPase (HAMAP MF_01389, InterPro:IPR004400, PANTHER:PTHR31715:SF0, Pfam:PF02492) containing a P-loop GTP-binding site at residues 24–31 (GPVGSGKT) and the invariant Cys72-Pro73-His74 (CPH) nickel-binding motif.
• Mechanistic Role: Couples GTP hydrolysis (GO:0003924 GTPase activity, GO:0005525 GTP binding) and nickel coordination (GO:0016151 nickel cation binding) to release $\text{Ni}^{2+}$ into the carbamylated active site of UreC (Vapar_4243, C5CY00) within the UreD-UreF-UreG pre-activation complex (PMID:10500143(https://pubmed.ncbi.nlm.nih.gov/10500143/); PMID:22369361(https://pubmed.ncbi.nlm.nih.gov/22369361/)). Linked to MODULE:urease_biogenesis_urea_hydrolysis (ureg_nickel_delivery / ureg_gtpase_metallochaperone).