and Relevance Tuberculosis still remains the number one cause of human mortality caused by infection with a bacterial pathogen. Estimates of mortality range from 1.4-2.0 million deaths globally per year. Current treatment paradigms, developed for drug sensitive strains of Mycobacterium tuberculosis, are being severely threatened by the emergence of multi- and extensively-drug-resistant strains. We have identified a cAMP-dependent protein acetyltransferase and sirtuin-like deacetylase in M. tuberculosis and have identified a small number of protein substrates for the protein acetyltransferase. These enzymes, when acetylated, lose their enzymatic activity, and when deacetylated, are again active. This reversible modification is likely to be important in the transition from rapid growth to a dormant, non-replicating phase. We will in Aim 1, continue our efforts to identify the substrate "cohort" for the protein acetyltransferase and identify growt conditions in which knock-out strains of the protein acetyltransferase or sirtuin are affected. Wit the development of strains of M. tuberculosis that can be grown in BSL2 laboratories, we propose in Aim 2 to identify the small molecule substrates of the 20 GNAT's in M. tuberculosis. We have developed reagents for this purpose, and will continue studies initiated in the prior period of support.
In Aim 3, we wish to examine the host proteins that are substrates for the M. tuberculosis EIS protein (EIS = enhanced intracellular survival), an acetyltransferase implicated in modulating the host response to bacterial infection and macrophage ingestion. Together these aims will provide a detailed description of the acetyltransferase enzymes, and their substrates, in an organism whose metabolism is poorly understood.
The translation of findings in the basic sciences into new therapeutics that will yield clinical success is the goal of scientists in both academia and the pharmaceutical industry. Despite extensive efforts from both camps, the development of new drugs has been slow, and in the case of antibiotics, almost nonexistent. This program leader has successfully taken some very fundamental laboratory findings and converted these into the successful treatment, and cure, of a number of individuals infected with extensively drug-resistant tuberculosis.
|Noy, Tahel; Xu, Hua; Blanchard, John S (2014) Acetylation of acetyl-CoA synthetase from Mycobacterium tuberculosis leads to specific inactivation of the adenylation reaction. Arch Biochem Biophys 550-551:42-9|
|Hazra, Saugata; Xu, Hua; Blanchard, John S (2014) Tebipenem, a new carbapenem antibiotic, is a slow substrate that inhibits the ?-lactamase from Mycobacterium tuberculosis. Biochemistry 53:3671-8|
|Serrano, Hector; Blanchard, John S (2013) Kinetic and isotopic characterization of L-proline dehydrogenase from Mycobacterium tuberculosis. Biochemistry 52:5009-15|
|Chow, Carmen; Xu, Hua; Blanchard, John S (2013) Kinetic characterization of hydrolysis of nitrocefin, cefoxitin, and meropenem by *-lactamase from Mycobacterium tuberculosis. Biochemistry 52:4097-104|
|Vergnolle, Olivia; Xu, Hua; Blanchard, John S (2013) Mechanism and regulation of mycobactin fatty acyl-AMP ligase FadD33. J Biol Chem 288:28116-25|
|Kurz, Sebastian G; Wolff, Kerstin A; Hazra, Saugata et al. (2013) Can inhibitor-resistant substitutions in the Mycobacterium tuberculosis *-Lactamase BlaC lead to clavulanate resistance?: a biochemical rationale for the use of *-lactam-*-lactamase inhibitor combinations. Antimicrob Agents Chemother 57:6085-96|
|Quartararo, Christine E; Hazra, Saugata; Hadi, Timin et al. (2013) Structural, kinetic and chemical mechanism of isocitrate dehydrogenase-1 from Mycobacterium tuberculosis. Biochemistry 52:1765-75|
|Wolfson-Stofko, Brett; Hadi, Timin; Blanchard, John S (2013) Kinetic and mechanistic characterization of the glyceraldehyde 3-phosphate dehydrogenase from Mycobacterium tuberculosis. Arch Biochem Biophys 540:53-61|
|Xu, Hua; Hegde, Subray S; Blanchard, John S (2011) Reversible acetylation and inactivation of Mycobacterium tuberculosis acetyl-CoA synthetase is dependent on cAMP. Biochemistry 50:5883-92|
|Sikora, Alison L; Wilson, Daniel J; Aldrich, Courtney C et al. (2010) Kinetic and inhibition studies of dihydroxybenzoate-AMP ligase from Escherichia coli. Biochemistry 49:3648-57|
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