GTP-binding protein that is not required for the biosynthesis of Mo-molybdopterin guanine dinucleotide (Mo-MGD) cofactor, and not necessary for the formation of active molybdoenzymes using this form of molybdenum cofactor. May act as an adapter protein to achieve the efficient biosynthesis and utilization of MGD. Displays a weak intrinsic GTPase activity. Is also able to bind the nucleotides ATP, TTP and GDP, but with lower affinity than GTP. kcat is 0.003 min(-1) for the GTPase activity. Homodimer. Interacts with MobA, MogA and MoeA in vivo. Is expressed at very low levels under both aerobic and anaerobic growth conditions. Belongs to the MobB family. Truncated N-terminus. Truncated N-terminus.