Thymidylate kinase of Mycobacterium tuberculosis: A chimera sharing properties common to eukaryotic and bacterial enzymes

Citation
H. Munier-lehmann et al., Thymidylate kinase of Mycobacterium tuberculosis: A chimera sharing properties common to eukaryotic and bacterial enzymes, PROTEIN SCI, 10(6), 2001, pp. 1195-1205
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
PROTEIN SCIENCE
ISSN journal
0961-8368 → ACNP
Volume
10
Issue
6
Year of publication
2001
Pages
1195 - 1205
Database
ISI
SICI code
0961-8368(200106)10:6<1195:TKOMTA>2.0.ZU;2-F
Abstract
We have overexpressed in Escherichia coli the thymidylate kinase of Mycobac terium tuberculosis (TMPKmt). Biochemical and physico-chemical characteriza tion of TMPKmt revealed distinct structural and catalytic features when com pared to its counterpart from yeast (TMPKy) or E. coli (TMPKec), Denaturati on of the dimeric TMPKmt by urea under equilibrium conditions was studied b y intrinsic fluorescence and circular dichroism (CD) spectroscopy. It sugge sted a three-state unfolding mechanism with a monomeric intermediate. On th e other hand, 3'-azido-3'-deoxythymidine monophosphate (AZT-MP), which is s ubstrate for TMPKy and TMPKec acts as a potent competitive inhibitor for TM PKmt. We propose a structural model of TMPKmt in which the overall fold des cribed in TMPKy and TMPKec is conserved and slight differences at the level of primary and SD-structure explain strong variations in the phosphorylati on rate of substrate analogs. According to the model, we synthesized dTMP a nalogs acting either as substrates or specific inhibitors of TMPKmt. This a pproach based on slight structural differences among similar proteins could be applied to other essential enzymes for the design of new species-specif ic antimicrobials.