alpha-Hemolysin, gamma-hemolysin, and leukocidin from Staphylococcus aureus: distant in sequence but similar in structure.
alpha-Hemolysin from Staphylococcus aureus assembles from a water-soluble, monomeric species to a membrane-bound heptamer on the surface of target cells, creating water-filled channels that lead to cell death and lysis. Staphylococcus aureus also produces the gamma-hemolysin and leukocidin toxins, which function as two component toxins in the disruption and lysis of erythrocytes and leukocytes. Analysis of the aligned sequences of alpha-hemolysin, gamma-hemolysin, and leukocidin in the context of the alpha-hemolysin heptamer structure supports the conclusion that even though the level of sequence identity between alpha-hemolysin and the gamma-hemolysin and leukocidin toxins is in the so-called twilight zone, the three-dimensional structures of the protomers are probably conserved. By analogy with alpha-hemolysin, gamma-hemolysin and leukocidin may also form oligomeric, transmembrane channels in which an antiparallel beta-barrel constitutes the primary membrane-embedded domain.
Gouaux
E
E
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA. jeg52@columbia.edu
Hobaugh
M
M
Song
L
L
D000595:Amino Acid Sequence; D017124:Conserved Sequence; D006460:Hemolysin Proteins / Q000737:chemistry*; D007956:Leukocidins / Q000737:chemistry*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000737:chemistry*
D006460:Hemolysin Proteins; D007956:Leukocidins; D046911:Macromolecular Substances