1h0m: Difference between revisions

The quorum sensing system allows bacteria to sense their cell density and, initiate an altered pattern of gene expression after a sufficient quorum, of cells has accumulated. In Agrobacterium tumefaciens, quorum sensing, controls conjugal transfer of the tumour- inducing plasmid, responsible, for plant crown gall disease. The core components of this system are the, transcriptional regulator TraR and its inducing ligand, N-(3-oxo-octanoyl)-L-homoserine lactone. This complex binds DNA and, activates gene expression. We have determined the crystal structure of, TraR in complex with its autoinducer and target DNA (PDB code 1h0m). The, protein is dimeric, with each monomer composed of an N-terminal domain, which binds the ligand in an enclosed cavity far from the dimerization, region, and a C-terminal domain, which binds DNA via a helix-turn-helix, motif. The structure reveals an asymmetric homodimer, with one monomer, longer than the other. The N-terminal domain resembles GAF/PAS domains, normally fused to catalytic signalling domains. In TraR, the gene fusion, is between a GAF/PAS domain and a DNA-binding domain, resulting in a, specific transcriptional regulator involved in quorum sensing.

1H0M is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Agrobacterium_tumefaciens Agrobacterium tumefaciens] with HSL as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AA1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1H0M OCA].  

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