Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B₁₂ delivery and repair.

ABSTRACT: G-proteins function as molecular switches to power cofactor translocation and confer fidelity in metal trafficking. The G-protein, MMAA, together with MMAB, an adenosyltransferase, orchestrate cofactor delivery and repair of B₁₂-dependent human methylmalonyl-CoA mutase (MMUT). The mechanism by which the complex assembles and moves a >1300 Da cargo, or fails in disease, are poorly understood. Herein, we report the crystal structure of the human MMUT-MMAA nano-assembly, which reveals a dramatic 180° rotation of the B₁₂ domain, exposing it to solvent. The complex, stabilized by MMAA wedging between two MMUT domains, leads to ordering of the switch I and III loops, revealing the molecular basis of mutase-dependent GTPase activation. The structure explains the biochemical

SUBMITTER: Mascarenhas R 

PROVIDER: S-EPMC10356863 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature