National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)
R35GM122510
米国
National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)
1DP2AI138259-01
米国
National Science Foundation (NSF, United States)
1749662
米国
引用
ジャーナル: Cell / 年: 2019 タイトル: Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers. 著者: Fengbin Wang / Yangqi Gu / J Patrick O'Brien / Sophia M Yi / Sibel Ebru Yalcin / Vishok Srikanth / Cong Shen / Dennis Vu / Nicole L Ing / Allon I Hochbaum / Edward H Egelman / Nikhil S Malvankar / 要旨: 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 ...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.