National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM122510
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
K99GM138756
米国
引用
ジャーナル: Nat Microbiol / 年: 2022 タイトル: Cryo-EM structure of an extracellular Geobacter OmcE cytochrome filament reveals tetrahaem packing. 著者: Fengbin Wang / Khawla Mustafa / Victor Suciu / Komal Joshi / Chi H Chan / Sol Choi / Zhangli Su / Dong Si / Allon I Hochbaum / Edward H Egelman / Daniel R Bond / 要旨: Electrically conductive appendages from the anaerobic bacterium Geobacter sulfurreducens were first observed two decades ago, with genetic and biochemical data suggesting that conductive fibres were ...Electrically conductive appendages from the anaerobic bacterium Geobacter sulfurreducens were first observed two decades ago, with genetic and biochemical data suggesting that conductive fibres were type IV pili. Recently, an extracellular conductive filament of G. sulfurreducens was found to contain polymerized c-type cytochrome OmcS subunits, not pilin subunits. Here we report that G. sulfurreducens also produces a second, thinner appendage comprised of cytochrome OmcE subunits and solve its structure using cryo-electron microscopy at ~4.3 Å resolution. Although OmcE and OmcS subunits have no overall sequence or structural similarities, upon polymerization both form filaments that share a conserved haem packing arrangement in which haems are coordinated by histidines in adjacent subunits. Unlike OmcS filaments, OmcE filaments are highly glycosylated. In extracellular fractions from G. sulfurreducens, we detected type IV pili comprising PilA-N and -C chains, along with abundant B-DNA. OmcE is the second cytochrome filament to be characterized using structural and biophysical methods. We propose that there is a broad class of conductive bacterial appendages with conserved haem packing (rather than sequence homology) that enable long-distance electron transport to chemicals or other microbial cells.