Reactive Chlorine Species Reversibly Inhibit DnaB Protein Splicing in Mycobacteria

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Inteins are mobile genetic elements that splice themselves out of host proteins.
• Conditional protein splicing (CPS) is regulated by environmental conditions.
• Reactive chlorine species (RCS) are oxidants found in various environments.

Purpose of the Study:

• To investigate the effect of RCS on DnaB intein splicing.
• To determine if RCS can regulate protein splicing in native bacterial hosts.
• To propose a novel stress response mechanism in mycobacteria.

Main Methods:

• In vitro splicing assays with DnaB inteins from Mycobacterium leprae and Mycobacterium smegmatis.
• In vivo reporter assays in Mycobacterium smegmatis to monitor DnaB intein activity.
• Testing the effects of hypochlorous acid and N-chlorotaurine on splicing.

Main Results:

• Hypochlorous acid and N-chlorotaurine reversibly inhibited DnaB intein splicing in vitro.
• RCS inhibited DnaB protein splicing in M. smegmatis.
• DnaB intein activity was shown to be responsive to RCS in a native host.

Conclusions:

• RCS represent a novel environmental condition that influences protein splicing.
• DnaB protein splicing inhibition by RCS suggests a new stress response in Mycobacterium.
• This regulation could pause essential processes like DNA replication during oxidative stress.