9BXA

Structure of Mnx H340A complex from Bacillus sp. PL-12

Summary for 9BXA

• Entry DOI: 10.2210/pdb9bxa/pdb
• EMDB information: 45001
• Descriptor: MnxG, MnxE, MnxF (3 entities in total)
• Functional Keywords: complex, multicopper oxidase, manganese biomineralization, metal transport
• Biological source: Bacillus sp. (in: firmicutes); More
• Total number of polymer chains: 7
• Total formula weight: 210976.58

Authors

Novikova, I.V.,Evans, J.E. (deposition date: 2024-05-22, release date: 2024-08-07, Last modification date: 2024-10-30)

Primary citation

Novikova, I.V.,Soldatova, A.V.,Moser, T.H.,Thibert, S.M.,Romano, C.A.,Zhou, M.,Tebo, B.M.,Evans, J.E.,Spiro, T.G.
Cryo-EM Structure of the Mnx Protein Complex Reveals a Tunnel Framework for the Mechanism of Manganese Biomineralization.
J.Am.Chem.Soc., 146:22950-22958, 2024

PubMed Abstract: The global manganese cycle relies on microbes to oxidize soluble Mn(II) to insoluble Mn(IV) oxides. Some microbes require peroxide or superoxide as oxidants, but others can use O directly, via multicopper oxidase (MCO) enzymes. One of these, MnxG from strain PL-12, was isolated in tight association with small accessory proteins, MnxE and MnxF. The protein complex, called Mnx, has eluded crystallization efforts, but we now report the 3D structure of a point mutant using cryo-EM single particle analysis, cross-linking mass spectrometry, and AlphaFold Multimer prediction. The β-sheet-rich complex features MnxG enzyme, capped by a heterohexameric ring of alternating MnxE and MnxF subunits, and a tunnel that runs through MnxG and its MnxEF cap. The tunnel dimensions and charges can accommodate the mechanistically inferred binuclear manganese intermediates. Comparison with the Fe(II)-oxidizing MCO, ceruloplasmin, identifies likely coordinating groups for the Mn(II) substrate, at the entrance to the tunnel. Thus, the 3D structure provides a rationale for the established manganese oxidase mechanism, and a platform for further experiments to elucidate mechanistic details of manganese biomineralization.

PubMed: 39056168
DOI: 10.1021/jacs.3c06537

Experimental method

ELECTRON MICROSCOPY (3.37 Å)