TY - JOUR
T1 - Detailed studies of the binding mechanism of the Sinorhizobium meliloti transcriptional activator ExpG to DNA
AU - Baumgarth, Birgit
AU - Bartels, Frank Wilco
AU - Anselmetti, Dario
AU - Becker, Anke
AU - Ros, Robert
PY - 2005/1
Y1 - 2005/1
N2 - The exopolysaccharide galactoglucan promotes the establishment of symbiosis between the nitrogen-fixing Gram-negative soil bacterium Sinorhizobium meliloti 2011 and its host plant alfalfa. The transcriptional regulator ExpG activates expression of galactoglucan biosynthesis genes by direct binding to the expA1, expGlexpD1 and expE1 promoter regions. ExpG is a member of the MarR family of regulatory proteins. Analysis of target sequences of an ExpG(His)6, fusion protein in the exp promoter regions resulted in the identification of a binding site composed of a conserved palindromic region and two associated sequence motifs. Association and dissociation kinetics of the specific binding of ExpG(His)6 to this binding site were characterized by standard biochemical methods and by single-molecule spectroscopy based on the atomic force microscope (AFM). Dynamic force spectroscopy indicated a distinct difference in the kinetics between the wild-type binding sequence and two mutated binding sites, leading to a closer understanding of the ExpG-DNA interaction.
AB - The exopolysaccharide galactoglucan promotes the establishment of symbiosis between the nitrogen-fixing Gram-negative soil bacterium Sinorhizobium meliloti 2011 and its host plant alfalfa. The transcriptional regulator ExpG activates expression of galactoglucan biosynthesis genes by direct binding to the expA1, expGlexpD1 and expE1 promoter regions. ExpG is a member of the MarR family of regulatory proteins. Analysis of target sequences of an ExpG(His)6, fusion protein in the exp promoter regions resulted in the identification of a binding site composed of a conserved palindromic region and two associated sequence motifs. Association and dissociation kinetics of the specific binding of ExpG(His)6 to this binding site were characterized by standard biochemical methods and by single-molecule spectroscopy based on the atomic force microscope (AFM). Dynamic force spectroscopy indicated a distinct difference in the kinetics between the wild-type binding sequence and two mutated binding sites, leading to a closer understanding of the ExpG-DNA interaction.
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U2 - 10.1099/mic.0.27442-0
DO - 10.1099/mic.0.27442-0
M3 - Article
C2 - 15632443
AN - SCOPUS:13444256651
VL - 151
SP - 259
EP - 268
JO - Journal of General Microbiology
JF - Journal of General Microbiology
SN - 1350-0872
IS - 1
ER -