ABSTRACT
Bacillus subtilis subsp. natto secrets a peptide pheromone, named ComXnatto pheromone, as an inducer for biofilm formation containing poly-γ-glutamic acid. Recently, the ComXnatto pheromone was identified to be a hexapeptide with an amino acid sequence of Lys-Trp-Pro-Pro-Ile-Glu, and the tryptophan residue was post-translationally modified with a farnesyl group. In order to determine the precise modification of the tryptophan residue, ComXnatto pheromone was synthesized using solid-phase peptide synthesis. Biological activity of the ComXnatto pheromone was then investigated. It was demonstrated that poly-γ-glutamic acid production were accelerated by ComXnatto pheromone at more than 1 nM in natto.
Subject(s)
Bacillus subtilis/metabolism , Pheromones/chemistry , Pheromones/metabolism , Polyglutamic Acid/analogs & derivatives , Quorum Sensing , Bacillus subtilis/chemistry , Molecular Structure , Pheromones/chemical synthesis , Polyglutamic Acid/biosynthesis , Polyglutamic Acid/chemistryABSTRACT
Bacillus subtilis subsp. natto produces poly-γ-glutamic acid under the control of quorum sensing. We identified ComXnatto pheromone as the quorum-sensing pheromone with an amino acid sequence of Lys-Trp-Pro-Pro-Ile-Glu and the tryptophan residue posttranslationally modified by a farnesyl group. ComXnatto pheromone is unique in the sense that the 5th tryptophan residue from the C-terminal is farnesylated.
Subject(s)
Bacillus subtilis/metabolism , Bacterial Proteins/metabolism , Pheromones/metabolism , Protein Processing, Post-Translational , Quorum Sensing/genetics , Tryptophan/metabolism , Amino Acid Sequence , Bacillus subtilis/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Molecular Sequence Data , Pheromones/chemistry , Pheromones/genetics , Polyglutamic Acid/biosynthesis , Prenylation , Protein Structure, TertiaryABSTRACT
Posttranslational isoprenylation of a tryptophan residue identified from Bacillus quorum sensing pheromone, ComX pheromone, is unique and essential for the bioactivity. A modifying enzyme, ComQ, forms ComX pheromone from the ComX precursor and isoprenyl pyrophosphate and exhibits moderate similarity to isoprenyl pyrophosphate synthases. We investigated non-conserved region in ComQ, corresponding to isopentenyl pyrophosphate binding region of the synthases, using in vitro cell-free isoprenylation. These results suggested that the only conserved aspartic acid residue in the region of ComQ is critical for enzyme activity and responsible for ComX binding. Our findings should contribute to basic understanding of the mechanism of tryptophan isoprenylation.
