Binds and hydrolyzes GTP (PubMed:18950999). Likely functions as a G-protein chaperone that assists AdoCbl cofactor delivery to the methylmalonyl-CoA mutase (MCM) ScpA and reactivation of the enzyme during catalysis. GTP + H2O = GDP + H(+) + phosphate Monomer. Interacts with the methylmalonyl-CoA mutase ScpA. Part of an operon that encodes enzymes converting succinate to propionate. Belongs to the SIMIBI class G3E GTPase family. ArgK/MeaB subfamily. Was originally thought to be a membrane protein kinase involved in phosphorylation of the AO and LAO periplasmic-binding proteins (PubMed:9733684). However, its role needs to be reexamined.