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Assaying for Inorganic Polyphosphate in Bacteria
07:20

Assaying for Inorganic Polyphosphate in Bacteria

Published on: January 21, 2019

Polyphosphate kinase is involved in stress-induced mprAB-sigE-rel signalling in mycobacteria

Kamakshi Sureka1, Supratim Dey, Pratik Datta

  • 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Calcutta 700009, India.

Molecular Microbiology
|July 17, 2007
PubMed

Insights

Polyphosphate kinase 1 (PPK1) is crucial for bacterial stress survival. This study shows PPK1 enables polyphosphate synthesis and is vital for the stringent response in mycobacteria, enhancing survival in harsh conditions.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Polyphosphate kinase 1 (PPK1) is essential for bacterial stress adaptation.
  • The role of PPK1 in mycobacteria, particularly in stress response pathways, requires further elucidation.

Purpose of the Study:

  • To characterize the function of PPK1 from Mycobacterium tuberculosis.
  • To investigate the role of PPK1 in the stringent response and stress survival of mycobacteria.

Main Methods:

  • Overexpression and characterization of Mycobacterium tuberculosis ppk1 in Escherichia coli.
  • Construction and analysis of a ppk1 knockout mutant in Mycobacterium smegmatis.
  • Investigation of gene transcription and regulator synthesis under various conditions.

Main Results:

  • Specific residues (R230, F176) critical for PPK1's polyphosphate synthesis and dimerization were identified.
  • A ppk1 knockout mutant showed impaired survival under hypoxia and defective stringent response (rel gene transcription, ppGpp synthesis).
  • PPK1 is essential for the mprAB-sigE-rel signaling pathway and survival of M. tuberculosis within macrophages.

Conclusions:

  • PPK1 is indispensable for polyphosphate synthesis, dimerization, and the stringent response in mycobacteria.
  • PPK1 plays a central role in mediating the mprAB-sigE-rel signaling cascade crucial for stress adaptation.
  • Polyphosphate, synthesized by PPK1, is a key molecule for mycobacterial survival under various stress conditions, including macrophage infection.

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