Aerolysin

In molecular biology, Aerolysin is a cytolytic pore-forming toxin exported by Aeromonas hydrophila, a Gram-negative bacterium associated with diarrhoeal diseases and deep wound infections.^[1][2] It is also produced by the caterpillar of the moth Megalopyge opercularis, sometimes called the Tree Asp. The mature toxin binds to eukaryotic cells and aggregates to form holes (approximately 3 nm in diameter) leading to the destruction of the membrane permeability barrier and osmotic lysis. The structure of proaerolysin has been determined to 2.8A resolution and shows the protoxin to adopt a novel fold.^[2] High-resolution cryo-EM atomic models of aerolysin in membrane-like environment (lipid copolymer Nanodiscs) as well as some prepore-like mutant have been elucidated, permitting the identification of important interactions required for pore formation and revealing four constriction rings in the pore lumen. ^[3]

Aerolysin
Aerolysin
Identifiers
Symbol	Aerolysin
Pfam	PF01117
Pfam clan	CL0345
InterPro	IPR005830
PROSITE	PDOC00247
SCOP2	9fm6 1pre, 9fm6 / 9fm6 SCOPe / 9fm6 SUPFAM
TCDB	1.C.4
OPM superfamily	35
OPM protein	9fm6 5jzt, 9fm6
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Aerolysin as a biosensor

Aerolysin has also been used as a biosensor due to its narrow lumen and four constrictions points^[3], which could be easily mutated, rendering aerolysin very sensitive^[4][5][6] for the detection of small molecules^[7], (cyclic^[8]) peptides^[9][10], polymers^[11][12], biopolymers such as DNA^[13] or RNA^[14], different sugars^[15] and also some proteins^[16].

Aerolysin has also been used as a tool to assess the action mechanism of the Hsp70 protein^[17] and to study the association mechanism to the membrane as well as pore formation with angle-resolved second harmonic scattering (AR-SHS), enabling to quantify quantitatively the affinity of aerolysin to lipids using liposomes^[18].