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


Autoria(s): 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
Data(s)

2014

Resumo

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]

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/48955/1/febs_jou_281-6_1613_2014.pdf

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.

Publicador

WILEY-BLACKWELL

Relação

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

http://eprints.iisc.ernet.in/48955/

Palavras-Chave #Molecular Biophysics Unit
Tipo

Journal Article

PeerReviewed