Subcellular localization of a germiantion-specific cortex-lytic enzyme, SleB, of Bacilli during sporulation

Genes Genet Syst. 2006 Jun;81(3):163-9. doi: 10.1266/ggs.81.163.


The subcellular localization of a germination-specific cortex-lytic enzyme, SleB, of Bacillus subtilis during sporulation was observed by using fusions of N-terminal region of SleB to the green fluorescent protein (GFP). A fusion with a putative peptidoglycan-binding motif (SleB1-108-GFP) formed a fluorescent ring around the forespore of the wild type strain, as expected from the known location of the intact SleB in the dormant spore. SleB1-108-GFP formed a similar fluorescent ring around the forespore of the gerE mutant which has a severe defect in the coat structure, and of the cwlD mutant which lacks a muramic delta-lactam unique to the spore peptidoglycan (cortex), whereas the fusion could not attach to the spore of the cwlDgerE mutant. By contrast, a fusion without the motif (SleB1-45-GFP) could not be recruited around the forespore of the gerE mutant though it appeared to be accumulated on the outside of the spore of the wild type strain. Since SleB was shown to degrade only the cortex with muramic delta-lactam, these results suggested that a proper localization of SleB requires a strict interaction between the motif of the enzyme and the delta-lactam structure of the cortex, not the formation of normal coat layer.

MeSH terms

  • Amidohydrolases / genetics
  • Amidohydrolases / metabolism*
  • Amino Acid Sequence
  • Bacillus subtilis / enzymology*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Genes, Reporter
  • Molecular Sequence Data
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Deletion
  • Spores, Bacterial / enzymology


  • Bacterial Proteins
  • Recombinant Fusion Proteins
  • SleB protein, Bacillus
  • Amidohydrolases