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Publication Abstract from PubMed

Response regulators (RRs), which undergo phosphorylation/dephosphorylation at aspartate residues, are highly prevalent in bacterial signal transduction. RRs typically contain an N-terminal receiver domain that regulates the activities of a C-terminal DNA binding domain in a phosphorylation-dependent manner. We present crystallography and solution NMR data for the receiver domain of Escherichia coli PhoB which show distinct 2-fold symmetric dimers in the inactive and active states. These structures, together with the previously determined structure of the C-terminal domain of PhoB bound to DNA, define the conformation of the active transcription factor and provide a model for the mechanism of activation in the OmpR/PhoB subfamily, the largest group of RRs. In the active state, the receiver domains dimerize with 2-fold rotational symmetry using their alpha4-beta5-alpha5 faces, while the effector domains bind to DNA direct repeats with tandem symmetry, implying a loss of intramolecular interactions.

Mechanism of activation for transcription factor PhoB suggested by different modes of dimerization in the inactive and active states.,Bachhawat P, Swapna GV, Montelione GT, Stock AM Structure. 2005 Sep;13(9):1353-63. PMID:16154092^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.