hly

Domain

The mushroom-shaped heptamer is composed of a cap domain (comprising 7 beta sandwiches and the amino latches of each protomer), 7 rim regions whose protruding strands may interact with the membrane bilayer, and the stem domain (52 Angstroms in length, 26 Angstroms in diameter) which forms the transmembrane pore.

Function

Alpha-toxin binds to the membrane of eukaryotic cells (particularly red blood cells, RBC) forming pores, resulting in hemolysis, with the release of low-molecular weight molecules leading to eventual osmotic RBC lysis (PubMed:1587866, PubMed:20624979). Human RBCs bind much less alpha-toxin than do rabbit RBCs (PubMed:1587866, PubMed:20624979). Heptamer oligomerization and pore formation is required for lytic activity (PubMed:1587866, PubMed:20624979).

Sequence Similarities

Belongs to the aerolysin family.

Cellular localization

• Secreted
• Secreted as a monomer (PubMed:8943190). After oligomerization and pore formation, the complex is translocated across the bilayer, probably via the Gly-rich domain of each strand.

Alternative names

hla, hly, Alpha-hemolysin, Alpha-HL, Alpha-toxin

Database links

swissprot:P09616 entrezGene:3920722 swissprot:Q2G1X0 entrezGene:1123836