Fig. 5: Cryo-EM structure of PQQ-loaded MxaF/MxaJ complex and the functions of auxiliary proteins in PQQ-dependent MDH maturation.
From: Deciphering the assembly process of PQQ dependent methanol dehydrogenase
a Sectional view of the cryo-EM structure of PQQ-loaded MxaF/MxaJ complex. MxaJ is shown in pink, and MxaF is shown in blue. A PQQ molecule embedded in MxaF is shown in green. b The Cα distance between two MxaF subunits from different MxaF/MxaJ complexes (PQQ-unloaded and PQQ-loaded) after alignment. c Close-up view of regions A100-D105 and G175-V180 of MxaF subunit in PQQ-unloaded MxaF/MxaJ complex (green), PQQ-loaded MxaF/MxaJ complex (blue), and complete MDH (PDB: 1H4I, gray). d Close-up view of G175-V180 region of MxaF in MxaF/MxaJ complex before (green) and after (blue) PQQ combination. Complete MDH (gray) is superimposed structurally, and the Ca2+ in MDH is shown in green sphere representation. e Close-up view of the interactions between MxaI (purple) and region G175-V180 of MxaF in complete MDH. The PQQ-unloaded and the PQQ-loaded MxaF/MxaJ complexes were superimposed with complete MDH structurally. f Interaction of the roof sheet with the main part of MxaF (gray) and MxaI (purple) in complete MDH. The position of roof sheet in MxaF/MxaJ complex is shown in green. Critical amino acid residues are shown in stick representation. g Model of chaperone-assisted PQQ-dependent MDH assembly process.
