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Allosteric regulation and substrate activation in cytosolic nucleotidase II from Legionella pneumophila

Srinivasan, Bharath and Forouhar, Farhad and Shukla, Arpit and Sampangi, Chethana and Kulkarni, Sonia and Abashidze, Mariam and Seetharaman, Jayaraman and Lew, Scott and Mao, Lei and Acton, Thomas B and Xiao, Rong and Everett, John K and Montelione, Gaetano T and Tong, Liang and Balaram, Hemalatha (2014) Allosteric regulation and substrate activation in cytosolic nucleotidase II from Legionella pneumophila. In: FEBS JOURNAL, 281 (6). pp. 1613-1628.

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Official URL: http://dx.doi.org/10.1111/febs.12727

Abstract

Cytosolic nucleotidase II (cN-II) from Legionellapneumophila (Lp) catalyzes the hydrolysis of GMP and dGMP displaying sigmoidal curves, whereas catalysis of IMP hydrolysis displayed a biphasic curve in the initial rate versus substrate concentration plots. Allosteric modulators of mammalian cN-II did not activate LpcN-II although GTP, GDP and the substrate GMP were specific activators. Crystal structures of the tetrameric LpcN-II revealed an activator-binding site at the dimer interface. A double mutation in this allosteric-binding site abolished activation, confirming the structural observations. The substrate GMP acting as an activator, partitioning between the allosteric and active site, is the basis for the sigmoidicity of the initial velocity versus GMP concentration plot. The LpcN-II tetramer showed differences in subunit organization upon activator binding that are absent in the activator-bound human cN-II structure. This is the first observation of a structural change induced by activator binding in cN-II that may be the molecular mechanism for enzyme activation. DatabaseThe coordinates and structure factors reported in this paper have been submitted to the Protein Data Bank under the accession numbers and . The accession number of GMP complexed LpcN-II is . Structured digital abstract <list list-type=''bulleted'' id=''febs12727-list-0001''> andby() andby() Structured digital abstract was added on 5 March 2014 after original online publication]

Item Type: Journal Article
Additional Information: copyright for this article belongs to WILEY-BLACKWELL, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Keywords: 5-nucleotidase; allostery; GMP-complexed LpcN-II structure; heterotropic activation; substrate activation
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Depositing User: Id for Latest eprints
Date Deposited: 26 May 2014 11:23
Last Modified: 22 Feb 2019 09:12
URI: http://eprints.iisc.ac.in/id/eprint/48955

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