Autoinducer-2
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| IUPAC name
(3aS,6S,6aR)-2,2,6,6a-tetrahydroxy-3a-methyltetrahydrofuro[3,2-d][1,3,2]dioxaborol-2-uide)
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Autoinducer-2 (AI-2), a furanosyl borate diester, is a member of a family of signaling molecules used in quorum sensing.[1][2] AI-2 is produced by both gram-negative and gram-positive bacteria.[3] AI-2 is sythesized by the reaction of 1-deoxy-3-dehydro-D-ribulose with boric acid.[4]
AI-2 is sensed by the Lsr transport cassette and is actively transported into the cell, where it is phosphorylated by LsrK. Then, Phospho-AI-2 binds the transcriptional repressor protein, LsrR, which subsequently is released from the promoter/operator region of the lsr operon – and transcription of the lsr genes is initiated. AI-2 signalling is also regulated by glucose and cAMP/CRP via the lsr operon. In the presence of glucose, low levels of cAMP/CRP result in almost no lsr operon (lsrABCDFG) expression. Without glucose, cAMP-CRP is needed to stimulate the lsr expression, while LsrR represses its expression in the absence of the inducer, phospho-AI-2. As AI-2 accumulates, more AI-2 is taken in via LsrABCD, phosphorylated via LsrK, and the lsr transcription is de-repressed, enabling even more AI-2 uptake.[5]
References
- ^ Cao, J.G.; Meighen, E.A. (1989). "Purification and structural identification of an autoinducer for the luminescence system of Vibrio harveyi". Journal of Biological Chemistry. 264 (36): 21670–21676.
{{cite journal}}:|access-date=requires|url=(help); Check date values in:|accessdate=(help) - ^ Miller, S.T. (2004). Molecular Cell. 15: 677–687.
{{cite journal}}:|access-date=requires|url=(help); Check date values in:|accessdate=(help); Missing or empty|title=(help) - ^ Miller, M. B.; Bassler, B. L. (2001). "Quorum sensing in bacteria". Annual Review of Microbiology. 55: 165–199. PMID 11544353.
{{cite journal}}:|access-date=requires|url=(help); Check date values in:|accessdate=(help) - ^ http://www.chem.qmul.ac.uk/iubmb/enzyme/reaction/misc/AI2.html
- ^ Wang, L. (2005). Journal of Bacteriology. 187: 2066–2076.
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