ATP-Dependent Mure Ligase in Mycobacterium Tuberculosis: Biochemical and Structural Characterisation.
Basavannacharya, C., Robertson, G., Munshi, T., Keep, N.H., Bhakta, S.(2010) Tuberculosis (Edinb) 90: 16
- PubMed: 19945347 
- DOI: https://doi.org/10.1016/j.tube.2009.10.007
- Primary Citation of Related Structures:  
2WTZ - PubMed Abstract: 
New therapies are required against Mycobacterium tuberculosis and its cell wall peptidoglycan biosynthesis is a potential therapeutic target. UDP-MurNAc-tripeptide ligase (MurE) is a member of the ATP-dependent ligase family, which incorporate amino acids including meso-diaminopimelic acid (m-DAP) into peptidoglycan during synthesis in a species-specific manner. In the present study, we have cloned, over-expressed, and characterised MurE from M. tuberculosis (Mtb-MurE). The crystal structure has been determined at 3.0A resolution in the presence of the substrate UDP-MurNAc-l-Ala-d-Glu (UAG). The activity of the enzyme was measured through estimating inorganic phosphate released in a non-radioactive high-throughput colourimetric assay. UDP-MurNAc-l-Ala-d-Glu-m-DAP (UMT) formation coupled to inorganic phosphate release was confirmed by HPLC and mass spectrometric analyses. Kinetic constants were determined for a range of natural substrates using optimised conditions. From our findings, it is evident that Mtb-MurE is highly specific in adding m-DAP to UDP-MurNAc-dipeptide and ATP-hydrolysis is an absolute requirement for its activity.
Organizational Affiliation: 
Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK.