Type III secretion protein HrcV / FHIPEP conserved site / Bacterial export FHIPEP family signature. / Type III secretion system FHIPEP / FHIPEP, domain 3 / FHIPEP, domain 4 / FHIPEP family 類似検索 - ドメイン・相同性
Natural Sciences and Engineering Research Council (NSERC, Canada)
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Howard Hughes Medical Institute (HHMI)
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ジャーナル: J Struct Biol / 年: 2020 タイトル: Cryo-EM analysis of the SctV cytosolic domain from the enteropathogenic E. coli T3SS injectisome. 著者: Dorothy D Majewski / Bronwyn J E Lyons / Claire E Atkinson / Natalie C J Strynadka / 要旨: The bacterial injectisome and flagella both rely on type III secretion systems for their assembly. The syringe-like injectisome creates a continuous channel between the bacterium and the host cell, ...The bacterial injectisome and flagella both rely on type III secretion systems for their assembly. The syringe-like injectisome creates a continuous channel between the bacterium and the host cell, through which signal-modulating effector proteins are secreted. The inner membrane pore protein SctV controls the hierarchy of substrate selection and may also be involved in energizing secretion. We present the 4.7 Å cryo-EM structure of the SctV cytosolic domain (SctV) from the enteropathogenic Escherichia coli injectisome. SctV forms a nonameric ring with primarily electrostatic interactions between its subunits. Molecular dynamics simulations show that monomeric SctV maintains a closed conformation, in contrast with previous studies on flagellar homologue FlhA. Comparison with substrate-bound homologues suggest that a conformational change would be required to accommodate binding partners.