Activation of an anti-bacterial toxin by the biosynthetic enzyme CysK: mechanism of binding, interaction specificity and competition with cysteine synthase.

ABSTRACT: Contact-dependent growth inhibition (CDI) is a wide-spread mechanism of inter-bacterial competition. CDI⁺ bacteria deliver CdiA-CT toxins into neighboring bacteria and produce specific immunity proteins that protect against self-intoxication. The CdiA-CT toxin from uropathogenic Escherichia coli 536 is a latent tRNase that is only active when bound to the cysteine biosynthetic enzyme CysK. Remarkably, the CysK:CdiA-CT binding interaction mimics the 'cysteine synthase' complex of CysK:CysE. The C-terminal tails of CysE and CdiA-CT each insert into the CysK active-site cleft to anchor the respective complexes. The dissociation constant for CysK:CdiA-CT (K _d ~ 11 nM) is comparable to that of the E. coli cysteine synthase complex (K _d ~ 6 nM), and both complexe

SUBMITTER: Benoni R 

PROVIDER: S-EPMC5562914 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature