title: Microbial Diversity: Application on micro-organisms for the biodegradation of xenobiotics
creator: Jain, R K
creator: Kapur, Manisha
creator: Labana, S
creator: Sarma, P.M.
creator: Lal, Banwari
creator: Bhattacharya, D.
creator: Thakur, I.S.
subject: QR Microbiology
description: The reason for secretion of nucleoside diphosphate  kinase (NdK), an enzyme involved in maintaining  the cellular pool of nucleoside triphosphates in both  prokaryotes and eukaryotes, by Mycobacterium  tuberculosis is intriguing. We recently observed  that NdK from M.tuberculosis (mNdK) localizes within  nuclei of HeLa and COS-1 cells and also nicks chromosomalDNAin  situ (A. K. Saini, K. Maithal, P. Chand,  S. Chowdhury, R. Vohra, A. Goyal, G. P. Dubey,  P. Chopra, R. Chandra, A. K. Tyagi, Y. Singh and  V. Tandon (2004) J. Biol. Chem., 279, 50142–50149).  In the current study, using a molecular beacon  approach, we demonstrate that the mNdK catalyzes  the cleavage of single strand DNA. It displays  Michaelis–Menten kinetics with a kcat/KM of 9.65  (–0.88) · 106 M�1 s�1. High affinity (Kd � KM of  �66 nM) and sequence-specific binding to the  sense strand of the nuclease hypersensitive region  in the c-myc promoter was observed. This is the  first study demonstrating that the cleavage reaction  is also enzyme-catalyzed in addition to the enzymatic  kinase activity of multifunctional NdK. Using  our approach, we demonstrate that GDP competitively  inhibits the nuclease activity with a KI of  �1.9 mM. Recent evidence implicates mNdK as a  potent virulence factor in tuberculosis owing to its  DNase-like activity. In this context, our results  demonstrate a molecular mechanism that could  be the basis for assessing in situ DNA damage by  secretory mNdK.
publisher: IISc
date: 2005
type: Article
type: PeerReviewed
format: application/pdf
identifier: http://crdd.osdd.net/open/992/1/jain2005.2.pdf
relation: http://nar.oxfordjournals.org/content/33/8/2707.full.pdf+html
identifier:   Jain, R K and Kapur, Manisha and Labana, S and Sarma, P.M. and Lal, Banwari and Bhattacharya, D. and Thakur, I.S.  (2005) Microbial Diversity: Application on micro-organisms for the biodegradation of xenobiotics.  Current Science, 89.  pp. 101-112.      
relation: http://crdd.osdd.net/open/992/