# The Cold Shock Protein CspB from Mycobacterium tuberculosis Binds to MTS0997 sRNA and MTS1338 sRNA as a Dimer

## TL;DR

This paper shows that the CspB protein from tuberculosis bacteria can bind to specific RNA molecules, suggesting it may help regulate gene expression during infection.

## Contribution

The study reveals that CspB from Mycobacterium tuberculosis forms a dimer and binds to MTS0997 and MTS1338 sRNAs, proposing a novel RNA chaperone role in mycobacteria.

## Key findings

- CspB from Mycobacterium tuberculosis forms a dimer due to its elongated C-terminal region.
- CspB binds with high affinity to MTS0997 sRNA and MTS1338 sRNA from the same organism.
- CspB is proposed to function as an RNA chaperone involved in mycobacterial pathogenesis.

## Abstract

RNA chaperones play a crucial role in the biogenesis and function of various RNAs in bacteria. They facilitate the interaction of small regulatory trans-encoded sRNAs with mRNAs, thereby significantly altering the pattern of gene expression in cells. This allows bacteria to respond quickly to changing environmental conditions, such as stress or adaptation to host organisms. Despite the identification of a large number of sRNAs in mycobacteria, none of the most common RNA chaperones have been found in their genomes. We determined the crystal structure of the cold shock protein CspB from Mycobacterium tuberculosis. It forms a dimer due to its elongated C-terminal region, which is a hairpin composed of two α-helices. It was also demonstrated that CspB from M. tuberculosis exhibits high affinity for MTS0997 sRNA and MTS1338 sRNA from the same organism, which is consistent with classical RNA chaperons such as Hfq and ProQ. Based on the putative RNA chaperone activity of bacterial proteins with cold-shock domains, we propose that CspB from M. tuberculosis may be involved in the regulation of mycobacterial pathogenesis through interaction with sRNAs.