Mycobacterial STAND Adenylyl Cyclases: The HTH Domain Binds DNA to Form Biocrystallized Nucleoids

Zaveri, A and Bose, A and Sharma, S and Rajendran, A and Biswas, P and Shenoy, AR and Visweswariah, SS (2020) Mycobacterial STAND Adenylyl Cyclases: The HTH Domain Binds DNA to Form Biocrystallized Nucleoids. In: Biophysical Journal . (In Press)

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Abstract

Mycobacteria harbor a unique class of adenylyl cyclases with a complex domain organization consisting of an N-terminal putative adenylyl cyclase domain fused to a nucleotide-binding adaptor shared by apoptotic protease-activating factor-1, plant resistance proteins, and CED-4 (NB-ARC) domain, a tetratricopeptide repeat (TPR) domain, and a C-terminal helix-turn-helix (HTH) domain. The products of the rv0891c-rv0890c genes represent a split gene pair, where Rv0891c has sequence similarity to adenylyl cyclases, and Rv0890c harbors the NB-ARC-TPR-HTH domains. Rv0891c had very low adenylyl cyclase activity so it could represent a pseudoenzyme. By analyzing the genomic locus, we could express and purify Rv0890c and find that the NB-ARC domain binds ATP and ADP, but does not hydrolyze these nucleotides. Using systematic evolution of ligands by exponential enrichment (SELEX), we identified DNA sequences that bound to the HTH domain of Rv0890c. Uniquely, the HTH domain could also bind RNA. Atomic force microscopy revealed that binding of Rv0890c to DNA was sequence independent, and binding of adenine nucleotides to the protein induced the formation of higher order structures that may represent biocrystalline nucleoids. This represents the first characterization of this group of proteins and their unusual biochemical properties warrant further studies into their physiological roles in future. © 2020 Biophysical Society

Item Type:	Journal Article
Publication:	Biophysical Journal
Publisher:	Biophysical Society
Additional Information:	Copyright to this article belongs to Biophysical Society
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	08 Jan 2021 08:24
Last Modified:	08 Jan 2021 08:24
URI:	http://eprints.iisc.ac.in/id/eprint/67548

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