Anaspec has announced the release of two structurally complex peptides, Agr D1 Thiolactone and Agr D2 Thiolactone, as part of its GO (catalogue) peptides offering.
In Gram-positive bacteria, such as in Staphylococcus aureus, physiological changes in the bacterial population are dependent on specific cell densities and growth phases (known as quorum sensing).
Staphylococcus aureus specifically uses quorum sensing to control the expression of exoproteins implicated in virulence through the Agr (accessory gene regulator) locus.
The Agr system is activated by an accumulation of extracellular mature peptide signals known as autoinducing peptides (AIPs).
Staphylococcus aureus has four distinct Agr groups, which exhibit bacterial interference.
Each Agr group synthesises a discrete AIP sequence.
All four AIP sequences are composed of seven to nine amino acids and have a thiolactone ring in the C-terminal five residues through a cysteine side chain.
Anaspec's chemists have synthesised and purified these peptides, which contain an intramolecular thiol ester linkage between the Cys (fifth amino acid from the C-terminus) and the C-terminal amino acid.
Mass spectrometry and HPLC were used to confirm the molecular weight and purity (greater than 95 per cent) of these peptides.
