1of9

SOLUTION STRUCTURE OF THE PORE FORMING TOXIN OF ENTAMOEBA HISTOLYTICA (AMOEBAPORE A)

spinqualitylabelsall models 1of9, 20 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1of9 is a 1 chain structure with sequence from Entamoeba histolytica. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [PFPA_ENTHI] Forms pores in the cytoplasmic membrane of host cells. Has antibacterial activity against M.luteus, no activity against E.coli. Implicated in the cytolytic activity of the parasite. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Amoebapore A is a 77-residue protein from the protozoan parasite and human pathogen Entamoeba histolytica. Amoebapores lyse both bacteria and eukaryotic cells by pore formation and play a pivotal role in the destruction of host tissues during amoebiasis, one of the most life-threatening parasitic diseases. Amoebapore A belongs to the superfamily of saposin-like proteins that are characterized by a conserved disulfide bond pattern and a fold consisting of five helices. Membrane-permeabilizing effector molecules of mammalian lymphocytes such as porcine NK-lysin and the human granulysin share these structural attributes. Several mechanisms have been proposed to explain how saposin-like proteins form membrane pores. All mechanisms indicate that the surface charge distribution of these proteins is the basis of their membrane binding capacity and pore formation. Here, we have solved the structure of amoebapore A by NMR spectroscopy. We demonstrate that the specific activation step of amoebapore A depends on a pH-dependent dimerization event and is modulated by a surface-exposed histidine residue. Thus, histidine-mediated dimerization is the molecular switch for pore formation and reveals a novel activation mechanism of pore-forming toxins. Solution structure of the pore-forming protein of Entamoeba histolytica.,Hecht O, Van Nuland NA, Schleinkofer K, Dingley AJ, Bruhn H, Leippe M, Grotzinger J J Biol Chem. 2004 Apr 23;279(17):17834-41. Epub 2004 Feb 17. PMID:14970207 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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