6EF8

Cryo-EM of the OmcS nanowires from Geobacter sulfurreducens

Summary for 6EF8

• Entry DOI: 10.2210/pdb6ef8/pdb
• EMDB information: 9046
• Descriptor: C-type cytochrome OmcS, HEME C (2 entities in total)
• Functional Keywords: helical symmetry, cytochrome nanowire, cytochrome c3, filament, electron transport
• Biological source: Geobacter sulfurreducens (strain ATCC 51573 / DSM 12127 / PCA)
• Total number of polymer chains: 7
• Total formula weight: 326879.18

Authors

Wang, F.,Gu, Y.,Egelman, E.H.,Malvankar, N.S. (deposition date: 2018-08-16, release date: 2019-04-10, Last modification date: 2024-10-16)

Primary citation

Wang, F.,Gu, Y.,O'Brien, J.P.,Yi, S.M.,Yalcin, S.E.,Srikanth, V.,Shen, C.,Vu, D.,Ing, N.L.,Hochbaum, A.I.,Egelman, E.H.,Malvankar, N.S.
Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers.
Cell, 177:361-369.e10, 2019

PubMed Abstract: Long-range (>10 μm) transport of electrons along networks of Geobacter sulfurreducens protein filaments, known as microbial nanowires, has been invoked to explain a wide range of globally important redox phenomena. These nanowires were previously thought to be type IV pili composed of PilA protein. Here, we report a 3.7 Å resolution cryoelectron microscopy structure, which surprisingly reveals that, rather than PilA, G. sulfurreducens nanowires are assembled by micrometer-long polymerization of the hexaheme cytochrome OmcS, with hemes packed within ∼3.5-6 Å of each other. The inter-subunit interfaces show unique structural elements such as inter-subunit parallel-stacked hemes and axial coordination of heme by histidines from neighboring subunits. Wild-type OmcS filaments show 100-fold greater conductivity than other filaments from a ΔomcS strain, highlighting the importance of OmcS to conductivity in these nanowires. This structure explains the remarkable capacity of soil bacteria to transport electrons to remote electron acceptors for respiration and energy sharing.

PubMed: 30951668
DOI: 10.1016/j.cell.2019.03.029

Experimental method

ELECTRON MICROSCOPY (3.7 Å)