A global response to sulfur starvation in Pseudomonas putida and its relationship to the expression of low-sulfur-content proteins

FEMS Microbiol Lett. 2007 Feb;267(2):184-93. doi: 10.1111/j.1574-6968.2006.00575.x. Epub 2006 Dec 20.

Abstract

Sulfur is essential for life on Earth, but its availability is limited in many environments. Here the sulfur-starvation response of the model soil bacterium Pseudomonas putida KT2440 is shown to be associated with an approximately fivefold reduction in the total soluble thiol content of the cell. A bioinformatic survey of the P. putida KT2440 genome identified 646 genes encoding proteins with a significantly lower than average sulfur content (low sulfur-content proteins, LSPs), the expression of which may have a role in the global reduction of cellular thiol content during sulfur starvation. Analysis of the genetic organization of the LSP-encoding genes showed that 31% were potentially transcriptionally associated with at least one other gene encoding a protein defined as an LSP. In particular, 55 LSP genes were located in three large clusters, termed low-sulfur islands (LSIs) here. The predicted identities of the proteins encoded by the LSIs strongly suggest that the LSIs have a role in acquiring sulfur from organic sulfur sources during sulfur starvation. This hypothesis was supported by transcription fusion studies on a limited number of LSP promoters under low-sulfur conditions. In a wider survey of bacterial species, LSIs were found to be more prevalent in free-living, Gram-negative bacteria than in Gram-positive or obligately intracellular bacteria.

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Computational Biology
  • Genome, Bacterial
  • Pseudomonas putida / genetics
  • Pseudomonas putida / metabolism*
  • Pseudomonas putida / physiology
  • Sulfhydryl Compounds / metabolism
  • Sulfur / metabolism*

Substances

  • Bacterial Proteins
  • Sulfhydryl Compounds
  • Sulfur