AIP-I YSTCDFIM (Thiolactone 4-8)
Quorum sensing peptide from S. aureus. Activates agr response, and expression of virulence factors and toxins
Catalogue number crb1000249 Molecular Weight 961.11 Sequence (one letter code) YSTCDFIM (Thiolactone 4-8) Sequence (three letter code) H-Tyr-Ser-Thr-Cys-Asp-Phe-Ile-Met (Thiolactone 4-8) Molecular Weight 961.11 Purity >95% References
Beavis and Novick (1995) Cell density control of staphylococcal virulence mediated by an octapeptide pheromone. PNAS, 92(26) 12055 PMID: 8618843
Thoendel et al (2011) Peptide Signaling in the Staphylococci. Chem. Rev. 111(1) 117 PMID: 21174435
Auto-inducing peptide (AIP) is a cyclic thiolactone quorum sensing peptide from Staphylococcus aureus which is responsible for activating the agr response. AIP is released from the bacteria and its extracellular concentration is then sensed by a two-component system on the bacterial surface, AgrC and AgrA. AgrC is the membrane histidine kinase receptor and AgrA is a response regulator; upon binding of AIP, AgrC phosphorylates AgrA.
AIP accumulates during growth activating an AgrC and AgrA cascade when it reaches a critical signal level. This cascade activates P2 and P3 promoters which autoactivate the agr system and upregulate RNAIII transcription. RNAIII regulates the expression of virulence factors including toxins, super-antigens, and exo-enzymes.
AgrD is the precursor peptide of AIP, and AgrB is an integral membrane endopeptidase essential to biosynthesize AIP. This AIP system is conserved among many Gram-positive bacteria.