Lysenin Toxin Membrane Insertion Is pH-Dependent but Independent of Neighboring Lysenins.

ABSTRACT: Pore-forming toxins form a family of proteins that act as virulence factors of pathogenic bacteria, but similar proteins are found in all kingdoms of life, including the vertebrate immune system. They are secreted as soluble monomers that oligomerize on target membranes in the so-called prepore state; after activation, they insert into the membrane and adopt the pore state. Lysenin is a pore-forming toxin from the earthworm Eisenida foetida, of which both the soluble and membrane-inserted structures are solved. However, the activation and membrane-insertion mechanisms have remained elusive. Here, we used high-speed atomic force microscopy to directly visualize the membrane-insertion mechanism. Changing the environmental pH from pH 7.5 to below pH 6.0 favored membrane insertion. We detected

SUBMITTER: Munguira ILB 

PROVIDER: S-EPMC5685674 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature