The Haemophilus influenzae HipBA toxin-antitoxin system adopts an unusual three-com-ponent regulatory mechanism.

Type II toxin-antitoxin (TA) systems encode two proteins: a toxin that inhibits cell growth and an antitoxin that neutralizes the toxin by direct inter-molecular protein-protein inter-actions. The bacterial HipBA TA system is implicated in persister formation. The Haemophilus influenzae HipBA TA system consists of a HipB antitoxin and a HipA toxin, the latter of which is split into two fragments, and here we investigate this novel three-com-ponent regulatory HipBA system. Structural and functional analysis revealed that HipAN corresponds to the N-ter-minal part of HipA from other bacteria and toxic HipAC is inactivated by HipAN, not HipB. This study will be helpful in understanding the detailed regulatory mechanism of the HipBAN+C system, as well as why it is constructed as a three-com-ponent system. © Ji Sung Koo et al. 2022.

Citation

Ji Sung Koo, Sung-Min Kang, Won-Min Jung, Do-Hee Kim, Bong-Jin Lee. The Haemophilus influenzae HipBA toxin-antitoxin system adopts an unusual three-com-ponent regulatory mechanism. IUCrJ. 2022 Sep 01;9(Pt 5):625-631

PMID: 36071804

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