Sandbox WWC6
From Proteopedia
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== Function == | == Function == | ||
| - | Hemolysins are most commonly proteins found in red blood cells that | + | Hemolysins are most commonly proteins found in red blood cells that allow for the rapid release of small molecules and ions across the membrane. <ref >https://en.wikipedia.org/wiki/Hemolysin#cite_note-pmid20692229-3</ref> or lipid biosurfactants that disrupt membrane composition resulting in cell lysis. Hemolysins act through disruption of the cell membrane. <ref>http://www.sciencedirect.com/science/article/pii/S0005273610002610</ref> Pore formation<ref name ="sod"/> is the olgomerization of the pore sunbunits within the membrane. The pore is quickly filled with water, ions, and small molecules that rapidly exit the cell, dissipating ionic gradients and membrane potential. Osmotic pressure causes a rapid swelling of the cell, leading to total rupture of the membrane <ref>http://www.ks.uiuc.edu/Research/hemolysin/<ref>. These proteins are important for some erythrocyte nutrient accession, but cause massive erythrocyte destruction in bacterial infection, specifically responsible forhemolytic anemia, which causes fatigue, pain, arrythmias, and even heart failure in affected individuals.<ref>http://www.nhlbi.nih.gov/health/health-topics/topics/ha/</ref> |
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==Pathogenic microorganisms== | ==Pathogenic microorganisms== | ||
| - | Pore-forming toxins have been shown to closely relate to the pathogenicity of the toxin-producing organism <ref>http://www.ncbi.nlm.nih.gov/pubmed/1930675<ref> Both gram positive and gram negative bacteria are producers of hemolysins, as well as some clinically relevant fungi. Toxin secretion facillitates the availability of water, ions, and small molecules like sugar for the secreting pathogen. | + | Pore-forming toxins have been shown to closely relate to the pathogenicity of the toxin-producing organism <ref>http://www.ncbi.nlm.nih.gov/pubmed/1930675<ref> Both gram positive and gram negative bacteria are producers of hemolysins, as well as some clinically relevant fungi. Toxin secretion facillitates the availability of water, ions, and small molecules like sugar for the secreting pathogen. Hemolysin producing pathogen are identified by their ability to lyse cells in vitro <ref>https://en.wikipedia.org/wiki/Hemolysin<ref> |
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==Mechanism== | ==Mechanism== | ||
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==Medical Implications== | ==Medical Implications== | ||
| - | Diseases caused by mutations in sodium channels can come in many forms. Some mutations affect skeletal, cardiac or smooth muscle, while others affect neural function. Common diseases include long QT syndrome, hyperkalemic periodic paralysis, hypokalemic periodic paralysis, myotonia fluctuans and myotonia permanens among many others. <ref name ="dis">http://neuromuscular.wustl.edu/mother/chan.html#SCN4A</ref> | ||
===Role in infection=== | ===Role in infection=== | ||
| - | Hemolysin lysis of red blood cells is a marker for many kinds of pathogenic infection characterized by | + | Hemolysin lysis of red blood cells is a marker for many kinds of pathogenic infection characterized by death of red blood cells. |
===Oncology=== | ===Oncology=== | ||
| - | + | Thermostable direct hemoslysin (TDH) is one type of hemolysin, secreted by ''Vibrio parahaemolyticus'', that may be linked to the down regulation of colo carcinoma cell proliferation <ref>http://www.sciencedirect.com/science/article/pii/S030441651200116X<ref> | |
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===Hemolytic anemia=== | ===Hemolytic anemia=== | ||
Hemolytic anemia occurs when lysis of red blood cells occurs are rates faster than they can be replaced by bone marrow. <ref>https://www.nhlbi.nih.gov/health/health-topics/topics/ha<ref> | Hemolytic anemia occurs when lysis of red blood cells occurs are rates faster than they can be replaced by bone marrow. <ref>https://www.nhlbi.nih.gov/health/health-topics/topics/ha<ref> | ||
Revision as of 12:02, 13 May 2016
Hemolysins [1] are a lipid or protein toxins secreted by pathogens that lyse erythrocyte and some bacterial cell membranes. These toxins belong to a family of microbial exotoxins called cytolysins, which act on a broad number of cells[2]. The primary function of peptide hemolysins is pore formation at the cell membranes creating acytolytic effect, and is achieved by the release of cytosolic ions and small molecules through the hydrophilic, transmembrane portion of the beta-barrel pore[3].
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Function
Hemolysins are most commonly proteins found in red blood cells that allow for the rapid release of small molecules and ions across the membrane. [1] or lipid biosurfactants that disrupt membrane composition resulting in cell lysis. Hemolysins act through disruption of the cell membrane. [2] Pore formation[3] is the olgomerization of the pore sunbunits within the membrane. The pore is quickly filled with water, ions, and small molecules that rapidly exit the cell, dissipating ionic gradients and membrane potential. Osmotic pressure causes a rapid swelling of the cell, leading to total rupture of the membrane [4]
Structure
Hemolysins have three structural variations: alpha, beta, and gamma. These hemolysin types are comprised of di-, hepta- or octomeric subunits.
- Alpha-hemolysin
Alpha hemolysin causes a partial lysis of red blood cells. The heptameric pore assembles from water-soluble subunits. The alpha subunit, depicted right, consists seven identical monomeric units that exhibit rotational symmetry in oligomerized form. Each distinct subunit is differently colored for easy identification. The beta-barrel transmembrane domain is 50 Å in length [5]
