The Non-catalytic ``Cap Domain'' of a Mycobacterial Metallophosphoesterase Regulates Its Expression and Localization in the Cell

Matange, Nishad and Podobnik, Marjetka and Visweswariah, Sandhya S (2014) The Non-catalytic ``Cap Domain'' of a Mycobacterial Metallophosphoesterase Regulates Its Expression and Localization in the Cell. In: JOURNAL OF BIOLOGICAL CHEMISTRY, 289 (32). pp. 22470-22481.

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Abstract

Despite highly conserved core catalytic domains, members of the metallophosphoesterase (MPE) superfamily perform diverse and crucial functions ranging from nucleotide and nucleic acid metabolism to phospholipid hydrolysis. Unique structural elements outside of the catalytic core called ``cap domains'' are thought to provide specialization to these enzymes; however, no directed study has been performed to substantiate this. The cap domain of Rv0805, an MPE from Mycobacterium tuberculosis, is located C-terminal to its catalytic domain and is dispensable for the catalytic activity of this enzyme in vitro. We show here that this C-terminal extension (CTE) mediates in vivo localization of the protein to the cell membrane and cell wall as well as modulates expression levels of Rv0805 in mycobacteria. We also demonstrate that Rv0805 interacts with the cell wall of mycobacteria, possibly with the mycolyl-arabinogalactan-peptidoglycan complex, by virtue of its C terminus, a hitherto unknown property of this MPE. Using a panel of mutant proteins, we identify interactions between active site residues of Rv0805 and the CTE that determine its association with the cell wall. Finally, we show that Rv0805 and a truncated mutant devoid of the CTE produce different phenotypic effects when expressed in mycobacteria. Our study thus provides a detailed dissection of the functions of the cap domain of an MPE and suggests that the repertoire of cellular functions of MPEs cannot be understood without exploring the modulatory effects of these subdomains.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOLOGICAL CHEMISTRY
Publisher:	AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Additional Information:	Copy right for this article belongs to the AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	24 Sep 2014 05:51
Last Modified:	24 Sep 2014 05:51
URI:	http://eprints.iisc.ac.in/id/eprint/49937

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