Probing the function of Mycobacterium tuberculosis catalase-peroxidase by site-directed mutagenesis.

Catalase-peroxidase is a multi-functional heme-dependent enzyme which is well known for its ability to carry out both catalatic and peroxidatic reactions. Catalase-peroxidase from Mycobacterium tuberculosis(mtCP) is of particular interest because this enzyme activates the pro-antitubercular drug isoniazid. It is estimated that 2 billion people are infected with M.

Enzyme-catalyzed mechanism of isoniazid activation in class I and class III peroxidases.

There is an urgent need to understand the mechanism of activation of the frontline anti-tuberculosis drug isoniazid by the Mycobacterium tuberculosis catalase-peroxidase. To address this, a combination of NMR spectroscopic, biochemical, and computational methods have been used to obtain a model of the frontline anti-tuberculosis drug isoniazid bound to the active site of the class III peroxidase, horseradish peroxidase C. This information has been used in combination with the new crystal structure of the M.

Crystal structure of Mycobacterium tuberculosis catalase-peroxidase.

The Mycobacterium tuberculosis catalase-peroxidase is a multifunctional heme-dependent enzyme that activates the core anti-tuberculosis drug isoniazid. Numerous studies have been undertaken to elucidate the enzyme-dependent mechanism of isoniazid activation, and it is well documented that mutations that reduce activity or inactivate the catalase-peroxidase lead to increased levels of isoniazid resistance in M. tuberculosis.

Addition of missing loops and domains to protein models by x-ray solution scattering.

Inherent flexibility and conformational heterogeneity in proteins can often result in the absence of loops and even entire domains in structures determined by x-ray crystallographic or NMR methods. X-ray solution scattering offers the possibility of obtaining complementary information regarding the structures of these disordered protein regions. Methods are presented for adding missing loops or domains by fixing a known structure and building the unknown regions to fit the experimental scattering data obtained from the entire particle.