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Bacterial kinases as potential targets for broad-spectrum antibiotics

Bacterial kinases as potential targets for broad-spectrum antibiotics
Bacterial kinases as potential targets for broad-spectrum antibiotics
Polyphosphate biosynthesis and the stringent response play an important role in the virulence of pathogenic bacteria. Our objective is to validate these pathways as an antimicrobial target and to identify inhibitors of the key enzymes polyphosphate kinase (PPK), (p)ppGpp synthetase I (RelA) and (p)ppGpp synthetase/hydrolase II (SpoT).

The role of polyphosphate and (p)ppGpp metabolism in Francisella virulence has been explored with deletion mutants. These exhibited defects for intracellular growth in macrophages and were attenuated in mice, indicating a key role for the FtPPK, FtRelA and FtSpoT in the virulence of Francisella.

The development of three in vitro activity assays will enable the discovery of PPK inhibitors. Ion-pairing HPLC analysis has been used to measure substrate kinetics, providing evidence that FtPPK belongs to the PPK2 superfamily with little preference between substrates (KM: ADP - 369 ?M; GDP - 624 ?M) as displayed by other PPK2 enzymes. 31P NMR spectroscopy has been used to monitor the overall time course of the PPK reaction. To facilitate high-throughput screening, a coupled luminescence based activity assay has been developed in a 96-well plate format. These assays can also be applied to the discovery of inhibitors for FtRelA and FtSpoT.

Understanding the structural basis of inhibitor action requires a crystal structure of the target enzyme. For FtPPK, a crystallisation screen has identified conditions for obtaining suitable crystals and data has been collected to 2.1 Å resolution.

Future studies will use the high throughput assay to identify PPK inhibitors; NMR and HPLC assays to characterise the mode of action and crystal structures of PPK:inhibitor complexes will identify the precise molecular interactions.
Batten, Laura Elizabeth
65a3e951-681e-43fb-b709-80762746925f
Batten, Laura Elizabeth
65a3e951-681e-43fb-b709-80762746925f
Roach, Peter
ca94060c-4443-482b-af3e-979243488ba9

Batten, Laura Elizabeth (2013) Bacterial kinases as potential targets for broad-spectrum antibiotics. University of Southampton, School of Chemistry, Doctoral Thesis, 269pp.

Record type: Thesis (Doctoral)

Abstract

Polyphosphate biosynthesis and the stringent response play an important role in the virulence of pathogenic bacteria. Our objective is to validate these pathways as an antimicrobial target and to identify inhibitors of the key enzymes polyphosphate kinase (PPK), (p)ppGpp synthetase I (RelA) and (p)ppGpp synthetase/hydrolase II (SpoT).

The role of polyphosphate and (p)ppGpp metabolism in Francisella virulence has been explored with deletion mutants. These exhibited defects for intracellular growth in macrophages and were attenuated in mice, indicating a key role for the FtPPK, FtRelA and FtSpoT in the virulence of Francisella.

The development of three in vitro activity assays will enable the discovery of PPK inhibitors. Ion-pairing HPLC analysis has been used to measure substrate kinetics, providing evidence that FtPPK belongs to the PPK2 superfamily with little preference between substrates (KM: ADP - 369 ?M; GDP - 624 ?M) as displayed by other PPK2 enzymes. 31P NMR spectroscopy has been used to monitor the overall time course of the PPK reaction. To facilitate high-throughput screening, a coupled luminescence based activity assay has been developed in a 96-well plate format. These assays can also be applied to the discovery of inhibitors for FtRelA and FtSpoT.

Understanding the structural basis of inhibitor action requires a crystal structure of the target enzyme. For FtPPK, a crystallisation screen has identified conditions for obtaining suitable crystals and data has been collected to 2.1 Å resolution.

Future studies will use the high throughput assay to identify PPK inhibitors; NMR and HPLC assays to characterise the mode of action and crystal structures of PPK:inhibitor complexes will identify the precise molecular interactions.

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Published date: 31 May 2013
Organisations: University of Southampton, Chemistry

Identifiers

Local EPrints ID: 360883
URI: https://eprints.soton.ac.uk/id/eprint/360883
PURE UUID: 985f1e34-a29b-4799-9ba2-936c2cd83d36
ORCID for Peter Roach: ORCID iD orcid.org/0000-0001-9880-2877

Catalogue record

Date deposited: 10 Jan 2014 14:06
Last modified: 14 Aug 2018 00:34

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Contributors

Author: Laura Elizabeth Batten
Thesis advisor: Peter Roach ORCID iD

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