Distinct properties of a hypoxia specific paralog of single stranded DNA binding (SSB) protein in mycobacteria

Singh, Amandeep and Vijayan, M and Varshney, Umesh (2018) Distinct properties of a hypoxia specific paralog of single stranded DNA binding (SSB) protein in mycobacteria. In: TUBERCULOSIS, 108 . pp. 16-25.

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Abstract

In addition to the canonical Single Stranded DNA Binding (SSBa) protein, many bacterial species, including mycobacteria, have a paralogous SSBb. The SSBb proteins have not been well characterized. While in B. subtilis, SSBb has been shown to be involved in genetic recombination; in S. coelicolor it mediates chromosomal segregation during sporulation. Sequence analysis of SSBs from mycobacterial species suggests low conservation of SSBb proteins, as compared to the conservation of SSBa proteins. Like most bacterial SSB proteins, M. smegmatis SSBb (MsSSBb) forms a stable tetramer. However, solution studies indicate that MsSSBb is less stable to thermal and chemical denaturation than MsSSBa. Also, in contrast to the 5-20 fold differences in DNA binding affinity between paralogous SSBs in other organisms, MsSSBb is only about two-fold poorer in its DNA binding affinity than MsSSBa. The expression levels of ssbB gene increased during UV and hypoxic stresses, while the levels of ssbA expression declined. A direct physical interaction of MsSSBb and RecA, mediated by the C-terminal tail of MsSSBb, was also established. The results obtained in this study indicate a role of MsSSBb in recombination repair during stress.

Item Type:	Journal Article
Publication:	TUBERCULOSIS
Publisher:	CHURCHILL LIVINGSTONE
Additional Information:	The copyright for this article belongs to CHURCHILL LIVINGSTONE
Keywords:	DNA repair; Recombination repair; Hypoxia; RecA; SSBb; Stress response
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	13 Nov 2019 04:55
Last Modified:	13 Nov 2019 04:56
URI:	http://eprints.iisc.ac.in/id/eprint/63909

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