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Publication Abstract from PubMed

Pore-forming toxins (PFT) are virulence factors that transform from soluble to membrane-bound states. The Yersinia YaxAB system represents a family of binary alpha-PFTs with orthologues in human, insect, and plant pathogens, with unknown structures. YaxAB was shown to be cytotoxic and likely involved in pathogenesis, though the molecular basis for its two-component lytic mechanism remains elusive. Here, we present crystal structures of YaxA and YaxB, together with a cryo-electron microscopy map of the YaxAB complex. Our structures reveal a pore predominantly composed of decamers of YaxA-YaxB heterodimers. Both subunits bear membrane-active moieties, but only YaxA is capable of binding to membranes by itself. YaxB can subsequently be recruited to membrane-associated YaxA and induced to present its lytic transmembrane helices. Pore formation can progress by further oligomerization of YaxA-YaxB dimers. Our results allow for a comparison between pore assemblies belonging to the wider ClyA-like family of alpha-PFTs, highlighting diverse pore architectures.

Structure and mechanism of the two-component alpha-helical pore-forming toxin YaxAB.,Brauning B, Bertosin E, Praetorius F, Ihling C, Schatt A, Adler A, Richter K, Sinz A, Dietz H, Groll M Nat Commun. 2018 May 4;9(1):1806. doi: 10.1038/s41467-018-04139-2. PMID:29728606^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.