Pore forming toxin, α-hemolysin

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====The α-hemolysin pore====
====The α-hemolysin pore====
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Displaying the surface illustrates clearly that there is <scene name='Luciferase/7ahlsurface/1'>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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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 19:46, 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.

Contents

ALPHA-HEMOLYSIN FROM STAPHYLOCOCCUS AUREUS

Publication Abstract from PubMed

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

 

Hemolysin (7ahl), resolution 1.89Å.

Drag the structure with the mouse to rotate

                                                  

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

  1. ↑ Menestrina G, Dalla Serra M, Comai M, Coraiola M, Viero G, Werner S, Colin DA, Monteil H, Prevost G. Ion channels and bacterial infection: the case of beta-barrel pore-forming protein toxins of Staphylococcus aureus. FEBS Lett. 2003 Sep 18;552(1):54-60. PMID:12972152

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


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