1upg
From Proteopedia
Crystal structure of the quorum-sensing protein TraM from Agrobacterium tumefaciens
Structural highlights
FunctionTRAM_RHIRD Negatively regulates conjugation and the expression of tra genes by antagonizing TraR/AAI-dependent activation. TraM may either bind or modify TraR or AAI making them unavailable. Alternatively, TraM may bind tra promoters preventing TraR activation. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTransfer of the tumor-inducing plasmid in Agrobacterium tumefaciens is controlled by a quorum-sensing system whose main components are the transcriptional regulator TraR and its autoinducer. This system allows bacteria to synchronize infection of the host plant when a "quorum" of cells has been reached. TraM is an A. tumefaciens protein involved in the regulation of this system because it binds to TraR and prevents it from binding DNA. As a first step to understanding the molecular basis for the regulation of TraR by TraM, we have determined the crystal structure of TraM at 1.65 A resolution. This protein is packed as a dimer, with each monomer consisting mainly of two antiparallel alpha helices. Monomers are tightly associated, with a large hydrophobic area buried upon dimerization. Secondly, we characterized the TraR-TraM complex in vitro. TraM (11.4 kDa, monomer molecular mass) binds tightly TraR (27 kDa, monomer molecular mass) forming a stable oligomeric complex that likely accounts for two TraR and two TraM dimers. Crystal structure of the quorum-sensing protein TraM and its interaction with the transcriptional regulator TraR.,Vannini A, Volpari C, Di Marco S J Biol Chem. 2004 Jun 4;279(23):24291-6. Epub 2004 Mar 24. PMID:15044488[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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