5gaq
From Proteopedia
Cryo-EM structure of the Lysenin Pore
Structural highlights
Function[TXL_EISFE] Pore-forming toxin that specifically binds sphingomyelin in the plasma membrane of various cells. Has hemolytic activity. Is also cytotoxic to spermatozoa of some species of invertebrates and many species of vertebrates and to amphibian larvae, guinea pig polymorphonuclear leukocytes, chicken fibroblasts, normal spleen cells and various tumor cells. Is lethal for various species of reptiles, amphibian, birds and mammals. Induces smooth muscle contraction. It binds sphingomyelin and induces hemolysis in the same manner as lysenin-related protein 2, and is 10 times more effective than lysenin-related protein 1.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedLysenin from the coelomic fluid of the earthworm Eisenia fetida belongs to the aerolysin family of small beta-pore-forming toxins (beta-PFTs), some members of which are pathogenic to humans and animals. Despite efforts, a high-resolution structure of a channel for this family of proteins has been elusive and therefore the mechanism of activation and membrane insertion remains unclear. Here we determine the pore structure of lysenin by single particle cryo-EM, to 3.1 A resolution. The nonameric assembly reveals a long beta-barrel channel spanning the length of the complex that, unexpectedly, includes the two pre-insertion strands flanking the hypothetical membrane-insertion loop. Examination of other members of the aerolysin family reveals high structural preservation in this region, indicating that the membrane-insertion pathway in this family is conserved. For some toxins, proteolytic activation and pro-peptide removal will facilitate unfolding of the pre-insertion strands, allowing them to form the beta-barrel of the channel. Cryo-EM structure of lysenin pore elucidates membrane insertion by an aerolysin family protein.,Bokori-Brown M, Martin TG, Naylor CE, Basak AK, Titball RW, Savva CG Nat Commun. 2016 Apr 6;7:11293. doi: 10.1038/ncomms11293. PMID:27048994[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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