Functional Properties of Oligomeric and Monomeric Forms of Helicobacter pylori VacA Toxin.

ABSTRACT: Helicobacter pylori VacA is a secreted toxin that assembles into water-soluble oligomeric structures and forms anion-selective membrane channels. Acidification of purified VacA enhances its activity in cell culture assays. Sites of protomer-protomer contact within VacA oligomers have been identified by cryoelectron microscopy, and in the current study, we validated several of these interactions by chemical cross-linking and mass spectrometry. We then mutated amino acids at these contact sites and analyzed the effects of the alterations on VacA oligomerization and activity. VacA proteins with amino acid charge reversals at interprotomer contact sites retained the capacity to assemble into water-soluble oligomers and retained cell-vacuolating activity. Introduction of paired cysteine substit

SUBMITTER: Caso GC 

PROVIDER: S-EPMC8594603 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature