+Search query
-Structure paper
Title | Cryo-EM structure of the Shigella type III needle complex. |
---|---|
Journal, issue, pages | PLoS Pathog, Vol. 16, Issue 2, Page e1008263, Year 2020 |
Publish date | Feb 24, 2020 |
Authors | Michele Lunelli / Antje Kamprad / Jörg Bürger / Thorsten Mielke / Christian M T Spahn / Michael Kolbe / |
PubMed Abstract | The Type III Secretion Systems (T3SS) needle complex is a conserved syringe-shaped protein translocation nanomachine with a mass of about 3.5 MDa essential for the survival and virulence of many Gram- ...The Type III Secretion Systems (T3SS) needle complex is a conserved syringe-shaped protein translocation nanomachine with a mass of about 3.5 MDa essential for the survival and virulence of many Gram-negative bacterial pathogens. This system is composed of a membrane-embedded basal body and an extracellular needle that deliver effector proteins into host cells. High-resolution structures of the T3SS from different organisms and infection stages are needed to understand the underlying molecular mechanisms of effector translocation. Here, we present the cryo-electron microscopy structure of the isolated Shigella T3SS needle complex. The inner membrane (IM) region of the basal body adopts 24-fold rotational symmetry and forms a channel system that connects the bacterial periplasm with the export apparatus cage. The secretin oligomer adopts a heterogeneous architecture with 16- and 15-fold cyclic symmetry in the periplasmic N-terminal connector and C-terminal outer membrane ring, respectively. Two out of three IM subunits bind the secretin connector via a β-sheet augmentation. The cryo-EM map also reveals the helical architecture of the export apparatus core, the inner rod, the needle and their intervening interfaces. |
External links | PLoS Pathog / PubMed:32092125 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.55 - 5.11 Å |
Structure data | EMDB-10040: Inner membrane ring and secretin N0 N1 domains of the Shigella type 3 secretion system EMDB-10045: Inner membrane ring of the Shigella type 3 secretion system EMDB-10046: Needle complex of the Shigella type 3 secretion system |
Source |
|
Keywords | PROTEIN TRANSPORT / type 3 secretion system / shigella / secretin / beta-sheet augmentation / ring-forming membrane protein / protein translocation / injectisome |