MoaB2 binds to SigA in Mycobacterium smegmatis and modulates its activity and biological stability
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ABSTRACT: In mycobacteria, SigA is the primary sigma factor. This essential protein binds to RNA polymerase (RNAP) and is responsible for initiating transcription of housekeeping genes. Our knowledge about this factor in medicinally important mycobacteria is limited. Here, we performed an unbiased search for interacting partners of Mycobacterium smegmatis SigA. The search revealed a number of proteins; prominent among them was MoaB2. The SigA-MoaB2 interaction was validated and characterized by several approaches, revealing that it does not require RNAP and is highly specific, as alternative sigma factors did not interact with MoaB2. The structure of MoaB2 was solved by crystallography and the unique, unstructured N-terminal domain of SigA was identified to play a role in the SigA-MoaB2 interaction. Functional experiments showed that MoaB2 inhibits SigA-dependent transcription and increases biological stability of SigA. We propose that MoaB2, by sequestering SigA, exerts a dual effect on the transcription apparatus, and has the potential to modulate gene expression. In summary, this study has uncovered a new binding partner of mycobacterial SigA, paving the way for future research of this phenomenon.
INSTRUMENT(S): Orbitrap Fusion Lumos
ORGANISM(S): Mycolicibacterium Smegmatis Mkd8
SUBMITTER: Martin Hubalek
LAB HEAD: Martin Hubálek
PROVIDER: PXD039468 | Pride | 2024-11-11
REPOSITORIES: Pride
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