Recombinant Streptococcus pneumoniae serotype 2 Pneumolysin (ply) (146:A→Missing), partial

Function

A cholesterol-dependent toxin that causes cytolysis by forming pores in cholesterol-containing host membranes. After binding to target membranes, the protein undergoes a major conformation change, leading to its insertion in the host membrane and formation of an oligomeric pore complex. Cholesterol is required for binding to host membranes, membrane insertion and pore formation; cholesterol binding is mediated by a Thr-Leu pair in the C-terminus. Can be reversibly inactivated by oxidation

Subcellular Location

Secreted; Host cell membrane (Multi-pass membrane protein)

Subunit

Elongated monomers align along their lengths, indicating intersubunit contacts and suggesting the prepore structure (PubMed:15851031, PubMed:26333773, PubMed:26403197, PubMed:27796097, PubMed:28323617). Modeling based on cryo-EM shows a homooligomeric pore complex containing 38-44 subunits; when inserted in the host membrane (Probable). The size of isolated pores is detergent-dependent; in amphipol A8-35 homogeneous rings form with 42 subunits (PubMed:28323617)

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