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Narayanan, Naveen and Banerjee, Arun and Jain, Deepti and Kulkarni, Dhananjaya S. and Sharma, Rahul and Nirwal, Shivlee and Rao, Desirazu N. and Nair, Deepak T. (2020) Tetramerization at Low pH Licenses DNA Methylation Activity of M.HpyAXI in the Presence of Acid Stress. Journal of Molecular Biology, 432 (2). pp. 324-342. ISSN 00222836

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Methylation of genomic DNA can influence the transcription profile of an organism and may generate phenotypic diversity for rapid adaptation in a dynamic environment. M.HpyAXI is a Type III DNA methyltransferase present in Helicobacter pylori and is upregulated at low pH. This enzyme may alter the expression of critical genes to ensure the survival of this pathogen at low pH inside the human stomach. M.HpyAXI methylates the adenine in the target sequence (5′-GCAG-3′) and shows maximal activity at pH 5.5. Type III DNA methyltransferases are found to form an inverted dimer in the functional form. We observe that M.HpyAXI forms a nonfunctional dimer at pH 8.0 that is incapable of DNA binding and methylation activity. However, at pH 5.5, two such dimers associate to form a tetramer that now includes two functional dimers that can bind and methylate the target DNA sequence. Overall, we observe that the pH-dependent tetramerization of M.HpyAXI ensures that the enzyme is licensed to act only in the presence of acid stress.

Item Type: Article
Subjects: Biomedical Science
Biochemical and Biophysical Sciences
Depositing User: RCB Library
Date Deposited: 17 Mar 2020 08:09
Last Modified: 17 Mar 2020 08:09
URI: http://rcb.sciencecentral.in/id/eprint/193

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