Pore forming toxin, α-hemolysin
From Proteopedia
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====The α-hemolysin pore==== | ====The α-hemolysin pore==== | ||
| - | Displaying the surface illustrates clearly that there is <scene name= | + | Displaying the surface illustrates clearly that there is <scene name='Luciferase/7ahlsurface/2'>a tunnel down the middle of the heptamer that leads to the formation of pores in the cell membrane</scene>, which is the structural basis for why these are toxins. Such pores are expectedly detrimental to the cell, allowing exodus of critical molecules, destroying the established membrane potential and ionic gradients, and contributing to osmotic swelling. {{Link Toggle FancyCartoonHighQualityView}}. |
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Revision as of 19:47, 31 January 2011
α-Hemolysin from Staphlococcus aureus is a pore-forming toxin made of seven repeats of an identical monomer arranged in a ring. The structural basis of the toxic activity was readily revealed when the structure of the ring was solved.
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ALPHA-HEMOLYSIN FROM STAPHYLOCOCCUS AUREUS
The structure of the Staphylococcus aureus alpha-hemolysin pore has been determined to 1.9 A resolution. Contained within the mushroom-shaped homo-oligomeric heptamer is a solvent-filled channel, 100 A in length, that runs along the sevenfold axis and ranges from 14 A to 46 A in diameter. The lytic, transmembrane domain comprises the lower half of a 14-strand antiparallel beta barrel, to which each protomer contributes two beta strands, each 65 A long. The interior of the beta barrel is primarily hydrophilic, and the exterior has a hydrophobic belt 28 A wide. The structure proves the heptameric subunit stoichiometry of the alpha-hemolysin oligomer, shows that a glycine-rich and solvent-exposed region of a water-soluble protein can self-assemble to form a transmembrane pore of defined structure, and provides insight into the principles of membrane interaction and transport activity of beta barrel pore-forming toxins.
Structure of staphylococcal alpha-hemolysin, a heptameric transmembrane pore., Song L, Hobaugh MR, Shustak C, Cheley S, Bayley H, Gouaux JE, Science. 1996 Dec 13;274(5294):1859-66. PMID:8943190
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Background
Staphylococcus aureus is often pathogenic to humans and relies on several virulence factors in the course of the infections. α-hemolysin is one such virulencce factor that forms pores in target cells[1].
About this Structure
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PDB entry
7ahl is a 7 chain structure of sequences from Staphylococcus aureus. Full crystallographic information is available from OCA.
Reference for the structure
- Song L, Hobaugh MR, Shustak C, Cheley S, Bayley H, Gouaux JE. Structure of staphylococcal alpha-hemolysin, a heptameric transmembrane pore. Science. 1996 Dec 13;274(5294):1859-66. PMID:8943190
Notes and Literature References
See Also
- 1lkf,2lkf& ,3lkf, Leukocidin F (Hlg B) from Staphylococcus aureus
- 1pvl, the F component of Panton-Valentine leucocidin from Staphylococcus aureus
- 3i5v, Beta Toxin from Staphylococcus aureus
- 2qk7, S-F Heterodimer Of Staphylococcus aureus Gamma-Hemolysin
- 1qoy, Hemolysin E of E. coli
- 3a57
- 3hp7
- 3fy3
Additional 3D Structures of α-Hemolysin
Additional Literature and Resources
- For additional information, see: Toxins
- David Briggs's Blog on α-hemolsyin, which served as a template for the original adaptation of 7ahl to this topic page.
- Pore-forming toxin at Wikipedia
- Page on Bacterial Toxin α-Hemolysin by Aleksei Aksimentiev and Klaus Schulten
Page started with original page seeded by OCA on Mon Feb 16 13:00:23 2009 for 7ahl
