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MtnK, methylthioribose kinase, is a starvation-induced protein in Bacillus subtilis

A Sekowska1, L Mulard, S Krogh

  • 1HKU-Pasteur Research Centre, Dexter HC Man Building, Sassoon Road, Pokfulam, Hong Kong, China. sekowska@hkucc.hku.hk

BMC Microbiology
|September 8, 2001
PubMed
Abstract

Insights

Methylthioribose recycling in Bacillus subtilis begins with phosphorylation by MtnK (methylthioribose kinase). Additional genes, mtnUVWXYZ, are also essential for this crucial metabolic pathway.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • Methylthioadenosine is a key spermidine synthesis byproduct in Bacillus subtilis.
  • Methylthioribose, a degradation product, serves as a sulfur source and quorum-sensing precursor.
  • The metabolic fate of methylthioribose in B. subtilis was previously unknown.

Purpose of the Study:

  • To elucidate the mechanism of methylthioribose recycling in Bacillus subtilis.
  • To identify the genes and enzymes involved in methylthioribose metabolism.
  • To understand the regulation of methylthioribose recycling under different conditions.

Main Methods:

  • Selection of trifluoromethylthioribose-resistant mutants.
  • Gene expression analysis (operon structure, S-box leader).
  • Bioinformatic analysis (Pfam database, ortholog clusters).

Main Results:

  • Identified MtnK (methylthioribose kinase) as the enzyme catalyzing the first step of methylthioribose recycling.
  • Demonstrated that mtnK is co-transcribed with mtnS in an abundant transcript.
  • Showed increased MtnK synthesis under carbon, sulfur, and nitrogen starvation.
  • Revealed that mtnK belongs to the choline kinase family (Pfam 01633).
  • Identified additional genes (mtnUVWXYZ) essential for methylthioribose recycling.

Conclusions:

  • Phosphorylation by MtnK is the initial step in methylthioribose recycling.
  • The mtnK gene (formerly ykrT) encodes MtnK.
  • Genes mtnUVWXYZ (formerly ykrUVWXYZ) are also critical for methylthioribose recycling.

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