Title

Distinct Mechanism Evolved for Mycobacterial RNA Polymerase and Topoisomerase I Protein-Protein Interaction

Authors

Srikanth Banda, Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International UniversityFollow
Nan Cao, Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International UniversityFollow
Yuk-Ching Tse-Dinh, Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International UniversityFollow

Date of this Version

9-15-2017

Document Type

Article

Rights

default

Abstract

We report here a distinct mechanism of interaction between topoisomerase I and RNA polymerase in Mycobacterium tuberculosis and Mycobacterium smegmatis that has evolved independently from the previously characterized interaction between bacterial topoisomerase I and RNA polymerase. Bacterial DNA topoisomerase I is responsible for preventing the hyper-negative supercoiling of genomic DNA. The association of topoisomerase I with RNA polymerase during transcription elongation could efficiently relieve transcription-driven negative supercoiling. Our results demonstrate a direct physical interaction between the C-terminal domains of topoisomerase I (TopoI-CTDs) and the β' subunit of RNA polymerase of M. smegmatis in the absence of DNA. The TopoI-CTDs in mycobacteria are evolutionarily unrelated in amino acid sequence and three-dimensional structure to the TopoI-CTD found in the majority of bacterial species outside Actinobacteria, including Escherichia coli. The functional interaction between topoisomerase I and RNA polymerase has evolved independently in mycobacteria and E. coli, with distinctively different structural elements of TopoI-CTD utilized for this protein-protein interaction. Zinc ribbon motifs in E. coli TopoI-CTD are involved in the interaction with RNA polymerase. For M. smegmatis TopoI-CTD, a 27-amino-acid tail that is rich in basic residues at the C-terminal end is responsible for the interaction with RNA polymerase. Overexpression of recombinant TopoI-CTD in M. smegmatis competed with the endogenous topoisomerase I for protein-protein interactions with RNA polymerase. The TopoI-CTD overexpression resulted in decreased survival following treatment with antibiotics and hydrogen peroxide, supporting the importance of the protein-protein interaction between topoisomerase I and RNA polymerase during stress response of mycobacteria.

DOI

10.1016/j.jmb.2017.08.011

Identifier

28843989

Comments

Pubmed Accepted Manuscript

Published in final edited form as: J Mol Biol. 2017 September 15; 429(19): 2931–2942. doi:10.1016/j.jmb.2017.08.011.

Recommended Citation

Banda S, Cao N, Tse-Dinh YC. Distinct Mechanism Evolved for Mycobacterial RNA Polymerase and Topoisomerase I Protein-Protein Interaction. J Mol Biol. 2017 Sep 15;429(19):2931-2942. doi: 10.1016/j.jmb.2017.08.011. Epub 2017 Aug 24. PMID: 28843989; PMCID: PMC5610943.