Molecular Playground/ClyA: Difference between revisions
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Pore-forming toxins (PFTs) are virulence factors secreted by pathogenic organisms. These are proteins that form transmembrane channels on target cell membranes. They cause cell death by making the cell membrane permeable, leading to osmotic imbalance and lysis. There are two classes of PFTs based on their secondary structure, alpha-PFTs and beta-PFTs. Cytolysin A (ClyA) is an alpha-PFT and is secreted by ''Salmonella'', ''Shigella'' and ''E. coli'' strains. | Pore-forming toxins (PFTs) are virulence factors secreted by pathogenic organisms. These are proteins that form transmembrane channels on target cell membranes. They cause cell death by making the cell membrane permeable, leading to osmotic imbalance and lysis. There are two classes of PFTs based on their secondary structure, alpha-PFTs and beta-PFTs. Cytolysin A (ClyA) is an alpha-PFT and is secreted by ''Salmonella'', ''Shigella'' and ''E. coli'' strains. | ||
==About | ==About Cytolysin A== | ||
<scene name='57/571278/Clya_monomer/2'>ClyA monomer in its inactive form</scene> | <scene name='57/571278/Clya_monomer/2'>ClyA monomer in its inactive form</scene> | ||
[[1QOY]] is a 34 kDa monomer from [http://en.wikipedia.org/wiki/Escherichia_coli ''Escherichia coli''] (''E. coli''). It is | [[1QOY]] is a 34 kDa monomer from [http://en.wikipedia.org/wiki/Escherichia_coli ''Escherichia coli''] (''E. coli''). It is an alpha-PFT comprised of four alpha helicies, a smaller fifth alpha helix, and a <B><font color="purple">beta tongue</font></B>. The <B><font color="blue">N-terminus</font></B> and the <B><font color="red">C-terminus</font></B> are highlighted. ClyA has been shown to form pores through a non-classical assembly pathway, excreted in oligomeric form in outer-membrane vesicles (OMV) as pre-pores. Only until ClyA reaches the target host membrane does it form the dodecameric PFT with hemolytic activity, possessing the ability to lyse the host cell. | ||
<scene name='57/571278/Clya_protomer/1'>ClyA protomer</scene> | <scene name='57/571278/Clya_protomer/1'>ClyA protomer</scene> | ||