Location and conformation of pantothenate and its derivatives in Mycobacterium tuberculosis pantothenate kinase: insights into enzyme action

Chetnani, Bhaskar and Kumar, Parimal and Abhinav, KV and Chhibber, Manmohan and Surolia, A and Vijayan, M (2011) Location and conformation of pantothenate and its derivatives in Mycobacterium tuberculosis pantothenate kinase: insights into enzyme action. In: Acta Crystallographica Section D, 67 (Part 9). pp. 774-783.

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Abstract

Previous studies of complexes of Mycobacterium tuberculosis PanK (MtPanK) with nucleotide diphosphates and non-hydrolysable analogues of nucleoside triphosphates in the presence or the absence of pantothenate established that the enzyme has dual specificity for ATP and GTP, revealed the unusual movement of ligands during enzyme action and provided information on the effect of pantothenate on the location and conformation of the nucleotides at the beginning and the end of enzyme action. The X-ray analyses of the binary complexes of MtPanK with pantothenate, pantothenol and N-nonylpantothenamide reported here demonstrate that in the absence of nucleotide these ligands occupy, with a somewhat open conformation, a location similar to that occupied by phosphopantothenate in the `end' complexes, which differs distinctly from the location of pantothenate in the closed conformation in the ternary `initiation' complexes. The conformation and the location of the nucleotide were also different in the initiation and end complexes. An invariant arginine appears to play a critical role in the movement of ligands that takes place during enzyme action. The work presented here completes the description of the locations and conformations of nucleoside diphosphates and triphosphates and pantothenate in different binary and ternary complexes, and suggests a structural rationale for the movement of ligands during enzyme action. The present investigation also suggests that N-alkylpantothenamides could be phosphorylated by the enzyme in the same manner as pantothenate.

Item Type:	Journal Article
Publication:	Acta Crystallographica Section D
Publisher:	International Union of Crystallography
Additional Information:	Copyright of this article belongs to International Union of Crystallography.
Keywords:	pantothenate kinase;Mycobacterium tuberculosis.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	28 Sep 2011 10:46
Last Modified:	22 Feb 2012 07:37
URI:	http://eprints.iisc.ac.in/id/eprint/40765

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