Rv1915 and Rv1916 from Mycobacterium tuberculosis H37Rv form in vitro protein-protein complex.

Monika Antil, Vibha Gupta

Biochimica et biophysica acta. General subjects 2022 Jun

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Mycobacterium tuberculosis (Mtb) isocitrate lyase (ICL) is an established drug target that facilitates Mtb persistence. Unlike other mycobacterial strains, where ICL2 is a single gene product, H37Rv has a split event, resulting in two tandemly coded icls - rv1915 and rv1916. Our recent report on functionality of individual Rv1915 and Rv1916, led to postulate the cooperative role of these proteins in pathogen's survival under nutrient-limiting conditions. This study investigates the possibility of Rv1915 and Rv1916 interacting and forming a complex. Pull down assay, activity assay, mass spectrometry and site directed mutagenesis was employed to investigate and validate Rv1915-Rv1916 complex formation. Rv1915 and Rv1916 form a stable complex in vitro, with enhanced ICL/MICL activities as opposed to individual proteins. Further, activities monitored in the presence of acetyl-CoA show significant increase for Rv1916 and the complex but not of Rv0467 and Rv1915Δ90CT. Both full length and truncated Rv1915Δ90CT can form complex, implying the absence of its C-terminal disordered region in complex formation. Further, in silico analysis and site-directed mutagenesis studies reveal Y64 and Y65 to be crucial residues for Rv1915-Rv1916 complex formation. This study uncovers the association between Rv1915 and Rv1916 and supports the role of acetyl-CoA in escalating the ICL/MICL activities of Rv1916 and Rv1915Δ90CT-Rv1916 complex. Partitioning of ICL2 into Rv1915 and Rv1916 that associates to form a complex in Mtb H37Rv, suggests its importance in signaling and regulation of metabolic pathway particularly in carbon assimilation. Copyright © 2022 Elsevier B.V. All rights reserved.

Citation

Monika Antil, Vibha Gupta. Rv1915 and Rv1916 from Mycobacterium tuberculosis H37Rv form in vitro protein-protein complex. Biochimica et biophysica acta. General subjects. 2022 Jun;1866(6):130130