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Structure of the dodecameric Yersinia enterocolitica secretin YscC and its trypsin-resistant core.

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Kowal Julia, Chami Mohamed, Ringler Philippe, Müller Shirley A, Kudryashev Mikhail, Castaño-Díez Daniel, Amstutz Marlise, Cornelis Guy R, Stahlberg Henning, Engel Andreas,
Project Electron Microscopy of Membrane Proteins
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Original article (peer-reviewed)

Journal Structure (London, England : 1993)
Volume (Issue) 21(12)
Page(s) 2152 - 61
Title of proceedings Structure (London, England : 1993)
DOI 10.1016/j.str.2013.09.012


The type III secretion system machinery, also known as the injectisome, delivers bacterial effector proteins into eukaryotic cells during infection. The outer membrane YscC secretin is a major part of Yersinia enterocolitica's injectisome and is among the first components to assemble, solely assisted by its pilotin, YscW. We have determined the three-dimensional structures of the native complex and its protease-resistant core to 12 Å resolution by cryo-electron microscopy (cryo-EM) and show that YscC forms a dodecameric complex. Cryo-EM of YscC reconstituted into proteoliposomes defines the secretin's membrane-spanning region. Native YscC consists of an outer membrane ring connected via a thin cylindrical wall to a conical, periplasmic region that exposes N-terminal petals connected by flexible linkers. These petals harbor the binding site of YscD, a component of the inner membrane ring. A change in their orientation adapts the length of the YscC secretin and facilitates its interaction with YscD.