Studies in mycobactin biosynthesis

Gómez Velasco, Anaximandro (2009). Studies in mycobactin biosynthesis. University of Birmingham. Ph.D.

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Abstract

Tuberculosis (TB) is the leading cause of infectious disease mortality in the world by a single bacterial pathogen, \(Mycobacterium\) \(tuberculosis\). Current TB chemotherapy remains useful in treating susceptible M. tuberculosis strains, however, the emergence of MDR-TB and XDR-TB demand the development of new drugs. Enzymes involved in mycobactin biosynthesis, low molecular weight iron chelators, do not have mammalian homologues; therefore they are considered potential targets for the development of new anti-TB drugs. The aims of this study were to identify potential inhibitors and to investigate the function of the \(mbtG\) and \(AmbtE\) and \(AMbtF\) genes during mycobactin biosynthesis. The full length of \(mbtB\) and the ArCP domain were successfully cloned and post-translationally modified by MtaA, a broad phosphopantetheinyl transferase from \(Stigmatella\) \(aurantiaca\), using \(Escherichia\) \(coli\). Inhibitors identified by virtual screening as well as 13 chemically synthesised PAS analogues were initially investigated in whole-cell assay against \(Mycobacterium\) \(bovis\) BCG Pasteur. Seven of these compounds had interesting growth inhibition under ironsufficient conditions. The \(mbtA\) gene was cloned and expressed as soluble protein using \(Mycobacterium\) \(smegmatis\) mc2155. Preliminary \(in\) \(vitro\) MbtA assays provided hints of its activity, although, the \(KM\) for SAL and ATP have not been determined yet. The \(mbtG\) and \(ambtE\) genes have been cloned and expressed in E. coli to further investigate their biochemical function in mycobactin biosynthesis.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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