MRC National Institute for Medical Research, London
Science for Health
This project is now closed
Characterisation and manipulation of feedback inhibition of histidine biosynthesis in M. tuberculosis
Project supervisor: Luiz Pedro de Carvalho (Mycobacterial Research)
Allosteric control of enzymes represents an ancient, highly conserved and efficient way of controlling enzymatic activity and flux through biochemical pathways. Efficiency comes from direct, specific and nearly instantaneous effects. One of the main allosteric control mechanisms is allosteric feedback inhibition, where the end product of the pathway inhibits the first committed step. These properties make allosteric inhibition an interesting alternative for drug discovery and a valuable control point for synthetic biology.
We have started a characterization of the allosteric feedback inhibition of M. tuberculosis (Mtb) ATP-phosphoribosyltransferase (MtATP-PRT), responsible for the first step of L -histidine biosynthesis (Pedreño et al, 2012). We have also screened a chemical library and discovered lead compounds that work as allosteric inhibitors and activators of MtATP-PRT (unpublished results).
The student working on this project will investigate the allosteric site of MtATP-PRT and its interactions with L-histidine, inhibitors and activators. These studies will be accomplished by a combination of mutagenesis, enzymology and structural biology (in collaboration with Philip Walker and Steve Gamblin). In addition, the student will investigate the basic physiology of this regulatory network and the advantages and disadvantages of targeting the allosteric site of MtATP-PRT for control of L-histidine biosynthesis in M. tuberculosis. These experiments will involve the use of wild-type and recombinant M. tuberculosis strains and will be carried out in category 3 laboratory. Targeted metabolomic approaches will be employed to monitor ex vivo L-histidine production.
Together these studies will shed light on the molecular mechanism of allosteric regulation of an essential enzyme, inform on the regulatory properties of L-histidine biosynthesis in M. tuberculosis and help to identify potential compounds that might be used to alter L-histidine levels in bacteria. These compounds might find applications in synthetic biology and in pharmacology of human diseases.
References
- Pedreño, S; Pisco, JP; Larrouy-Maumus, G; Kelly, G and de Carvalho, LPS (2012)
Mechanism of feedback allosteric inhibition of ATP phosphoribosyltransferase.
Biochemistry In press. Publishers' abstract
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