Pneumolysin

Pneumolysin is a protein that is produced by the bacteria Streptococcus pneumoniae. It is a type of pore-forming toxin, which means it can create holes in the membranes of cells, leading to cell death. Pneumolysin is a key factor in the virulence of S. pneumoniae, and is involved in the pathogenesis of diseases such as pneumonia, meningitis, and otitis media.

Structure and Function

Pneumolysin is a 53 kDa protein that is composed of 471 amino acids. It is a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins. Pneumolysin binds to cholesterol in the cell membrane, and then oligomerizes to form a large pore. This pore allows ions and small molecules to pass freely across the membrane, disrupting the normal function of the cell and ultimately leading to cell death.

Role in Disease

Pneumolysin plays a crucial role in the pathogenesis of diseases caused by S. pneumoniae. It can damage the epithelial cells lining the respiratory tract, facilitating the invasion of the bacteria. In addition, pneumolysin can activate the immune system, leading to inflammation and tissue damage. It can also inhibit the function of immune cells, helping the bacteria to evade the immune response.

Clinical Significance

Because of its role in disease, pneumolysin is a target for vaccine development. Vaccines that can induce the immune system to produce antibodies against pneumolysin could potentially protect against infection with S. pneumoniae. In addition, drugs that can inhibit the function of pneumolysin could be used to treat infections with this bacteria.

See Also

• Streptococcus pneumoniae
• Pore-forming toxin
• Cholesterol-dependent cytolysin

References

Pneumolysin Resources
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