Haobo Guo - Structure and Conformational Dynamics of the Metalloregulator MerR upon Binding of Hg(II)

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  Publication Details (including relevant citation   information):

  Guo, H.B. et al. J. Mol. Biol. 2010,   398, 555-568.


  The bacterial metalloregulator MerR is the index case of an   eponymous family of regulatory proteins, which controls the   transcription of a set of genes (the mer operon) conferring   mercury resistance in many bacteria. Homodimeric MerR represses   transcription in the absence of mercury and activates   transcription upon Hg(II) binding. Here, the average structures   of the apo and Hg(II)-bound forms of MerR in aqueous solution are   examined using small-angle X-ray scattering, indicating an   extended conformation of the metal-bound protein and revealing   the existence of a novel compact conformation in the absence of   Hg(II). Molecular dynamics (MD) simulations are performed to   characterize the conformational dynamics of the Hg (II)-bound   form. In both small-angle X-ray scattering and MD, the average   torsional angle between DNA-binding domains is similar to 65   degrees. Furthermore, in MD, interdomain motions on a timescale   of similar to 10 ns involving large-amplitude (similar to 20   angstrom) domain opening-and-closing, coupled to similar to 40   degrees variations of interdomain torsional angle, are revealed.   This correlated domain motion may propagate allosteric changes   from the metal-binding site to the DNA-binding site while   maintaining DNA contacts required to initiate DNA underwinding.   (C) 2010 Elsevier Ltd. All rights reserved.

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