The Crystal Structure of Pneumolysin at 2.0 Å Resolution Reveals the Molecular Packing of the Pre-pore Complex.
Pneumolysin is a cholesterol-dependent cytolysin (CDC) and virulence factor of Streptococcus pneumoniae. It kills cells by forming pores assembled from oligomeric rings in cholesterol-containing membranes. Cryo-EM has revealed the structures of the membrane-surface bound pre-pore and inserted-pore oligomers, however the molecular contacts that mediate these oligomers are unknown because high-resolution information is not available. Here we have determined the crystal structure of full-length pneumolysin at 1.98 Å resolution. In the structure, crystal contacts demonstrate the likely interactions that enable polymerisation on the cell membrane and the molecular packing of the pre-pore complex. The hemolytic activity is abrogated in mutants that disrupt these intermolecular contacts, highlighting their importance during pore formation. An additional crystal structure of the membrane-binding domain alone suggests that changes in the conformation of a tryptophan rich-loop at the base of the toxin promote monomer-monomer interactions upon membrane binding by creating new contacts. Notably, residues at the interface are conserved in other members of the CDC family, suggesting a common mechanism for pore and pre-pore assembly.
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Jamie E
JE
Marshall
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Bayan H A
BH
Faraj
Department of Biochemistry, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Alexandre R
AR
Gingras
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Rana
R
Lonnen
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Md Arif
MA
Sheikh
Department of Biochemistry, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Mohammed
M
El-Mezgueldi
Department of Biochemistry, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Peter C E
PC
Moody
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Peter W
PW
Andrew
Department of Infection, Immunity and Inflammation, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.|Department of Biochemistry, University of Leicester, PO Box 138, Leicester, LE1 9HN UK.
Russell
R
Wallis
D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D018272:Porins / Q000737:chemistry* / Q000648:ultrastructure*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013301:Streptolysins / Q000737:chemistry*
D001426:Bacterial Proteins; D008051:Lipid Bilayers; D018272:Porins; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae