2avx | pdb_00002avx
solution structure of E coli SdiA1-171
Structural highlights
Function[SDIA_ECOLI] Activates cell division by specifically increasing transcription from one of the two promoters that lie immediately upstream of the ftsQAZ gene cluster. Activates ydiV expression in response to extracellular autoinducer AI-1 (Vibrio fischeri autoinducer oxoC6).[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe three-dimensional structure of a complex between the N-terminal domain of the quorum sensing protein SdiA of Escherichia coli and a candidate autoinducer N-octanoyl-L-homoserine lactone (C8-HSL) has been calculated in solution from NMR data. The SdiA-HSL system shows the "folding switch" behavior that has been seen for quorum-sensing factors produced by other bacterial species. In the presence of C8-HSL, a significant proportion of the SdiA protein is produced in a folded, soluble form in an E.coli expression system, whereas in the absence of acyl homoserine lactones, the protein is expressed into insoluble inclusion bodies. In the three-dimensional structure, the autoinducer molecule is sequestered in a deep pocket in the hydrophobic core, forming an integral part of the core packing of the folded SdiA. The NMR spectra of the complex show that the bound C8-HSL is conformationally heterogeneous, either due to motion within the pocket or to heterogeneity of the bound structure. The C8-HSL conformation is defined by NOEs to the protein only at the terminal methyl group of the octanoyl chain. Unlike other well-studied bacterial quorum sensing systems such as LuxR of Vibrio fischeri and TraR of Agrobacterium tumefaciens, there is no endogenous autoinducer for SdiA in E.coli: the E.coli genome does not contain a gene analogous to the LuxI and TraI autoinducer synthetases. We show that two other homoserine lactone derivatives are also capable of acting as a folding-switch autoinducers for SdiA. The observed structural heterogeneity of the bound C8-HSL in the complex, together with the variety of autoinducer-type molecules that can apparently act as folding switches in this system, are consistent with the postulated biological function of the SdiA protein as a detector of the presence of other species of bacteria. Structure of the Escherichia coli quorum sensing protein SdiA: activation of the folding switch by acyl homoserine lactones.,Yao Y, Martinez-Yamout MA, Dickerson TJ, Brogan AP, Wright PE, Dyson HJ J Mol Biol. 2006 Jan 13;355(2):262-73. Epub 2005 Nov 8. PMID:16307757[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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