This title appears in the Scientific Report : 2013 

Structure and function of a unique pore-forming protein from a pathogenic acanthamoeba
Michalek, Matthias
Sönnichsen, Frank D / Wechselberger, Rainer / Dingley, Andrew / Hung, Chien-Wen / Kopp, Annika / Wienk, Hans / Simanski, Maren / Herbst, Rosa / Lorenzen, Inken / Marciano-Cabral, Francine / Gelhaus, Christoph / Gutsmann, Thomas / Tholey, Andreas / Grötzinger, Joachim / Leippe, Matthias (Corresponding author)
Strukturbiochemie ; ICS-6
Nature Chemical Biology, 9 (2012) 1, S. 37 - 42
Nature Publishing Group 2013
10.1038/nchembio.1116
23143413
Journal Article
Structural Biology
Please use the identifier: http://dx.doi.org/10.1038/nchembio.1116 in citations.
Human pathogens often produce soluble protein toxins that generate pores inside membranes, resulting in the death of target cells and tissue damage. In pathogenic amoebae, this has been exemplified with amoebapores of the enteric protozoan parasite Entamoeba histolytica. Here we characterize acanthaporin, to our knowledge the first pore-forming toxin to be described from acanthamoebae, which are free-living, bacteria-feeding, unicellular organisms that are opportunistic pathogens of increasing importance and cause severe and often fatal diseases. We isolated acanthaporin from extracts of virulent Acanthamoeba culbertsoni by tracking its pore-forming activity, molecularly cloned the gene of its precursor and recombinantly expressed the mature protein in bacteria. Acanthaporin was cytotoxic for human neuronal cells and exerted antimicrobial activity against a variety of bacterial strains by permeabilizing their membranes. The tertiary structures of acanthaporin's active monomeric form and inactive dimeric form, both solved by NMR spectroscopy, revealed a currently unknown protein fold and a pH-dependent trigger mechanism of activation.