Allosteric regulation and substrate activation in cytosolic nucleotidase II from Legionella pneumophila. (17th February 2014)

• Record Type: Journal Article
• Authors: Srinivasan, Bharath; Forouhar, Farhad; Shukla, Arpit; Sampangi, Chethana; Kulkarni, Sonia; Abashidze, Mariam; Seetharaman, Jayaraman; Lew, Scott; Mao, Lei; Acton, Thomas B.; Xiao, Rong; Everett, John K.; Montelione, Gaetano T.; Tong, Liang; Balaram, Hemalatha
• Is Part Of: FEBS journal. Volume 281:Number 6(2014)
• Page Start: 1613
• Page End: 1628
• Publication Date: 2014-02-17
• Subjects: Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pathology, Molecular -- Periodicals; 572
• DOI: 10.1111/febs.12727
• Languages: English
• ISSNs: 1742-464X

Abstract

<abstract abstract-type="main" id="febs12727-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="febs12727-sec-0001" sec-type="section"> <p>Cytosolic nucleotidase II (cN‐II) from <italic>Legionella pneumophila</italic> (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.</p> </sec> <sec id="febs12727-sec-0002" sec-type="section"> <title>Database</title> <p>The coordinates and structure factors reported in this paper have been submitted to the Protein Data Bank under the accession numbers <ext-link ext-link-type="uri" xlink:href="http://www.rcsb.org/pdb/search/structidSearch.do?structureId=2BDE" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">2BDE</ext-link> and <ext-link ext-link-type="uri" xlink:href="http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4G63" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">4G63</ext-link>. The accession number of GMP complexed LpcN‐II is <ext-link ext-link-type="uri" xlink:href="http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4OHF" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">4OHF</ext-link>.</p> </sec> <sec id="febs12727-sec-0103" sec-type="section"> <title>Structured digital abstract</title> <p> <list id="febs12727-list-0001" list-type="bullet"> <list-item> <p> <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/Q5ZZB6" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">LpcN-II</ext-link> and <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/Q5ZZB6" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">LpcN-II</ext-link> <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0407" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">bind</ext-link> by <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0071" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">molecular sieving</ext-link> (<ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/intact/interaction/EBI-9087541" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">View interaction</ext-link>)</p> </list-item> <list-item> <p> <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/Q5ZZB6" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">LpcN-II</ext-link> and <ext-link ext-link-type="uri" xlink:href="http://www.uniprot.org/uniprot/Q5ZZB6" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">LpcN-II</ext-link> <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0407" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">bind</ext-link> by <ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0114" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">x-ray crystallography</ext-link> (<ext-link ext-link-type="uri" xlink:href="http://www.ebi.ac.uk/intact/interaction/EBI-9087519" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">View interaction</ext-link>)</p> </list-item> </list> </p> <p>[Structured digital abstract was added on 5 March 2014 after original online publication]</p> </sec> </abstract>