Cooper, A., Mcalpine, A., and Stockley, P.G. (1994) Calorimetric Studies of the Energetics of Protein-Dna Interactions in the Escherichia-Coli Methionine Repressor (Metj) System. Febs Letters, 348 (1). pp. 41-45. ISSN 0014-5793 (doi:10.1016/0014-5793(94)00579-6)
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Publisher's URL: http://dx.doi.org/10.1016/0014-5793(94)00579-6
Calorimetric measurements of binding of a specific DNA fragment and S-adenosyl methionine (SAM) co-repressor molecules to the E. coli methionine repressor (MetJ) show significant differences in the energetics of binary and ternary protein-DNA complexes. Formation of the MetJ:SAM:DNA ternary complex is significantly more exothermic (Delta H similar or equal to -99 kJ.mol(-1)) than either MetJ:DNA or MetJ:SAM binary complexes alone (Delta H similar or equal to -10 kJ.mol(-1) each). The protein is also significantly more stable to unfolding (Delta T-m similar or equal to 5.4 degrees C) when bound to DNA. These observations suggest that binding of SAM to the protein-DNA complex leads to a significant reduction in dynamic flexibility of the ternary complex, with considerable entropy-enthalpy compensation, not necessarily involving any overall conformational change.
|Glasgow Author(s):||Cooper, Prof Alan|
|Authors:||Cooper, A., Mcalpine, A., and Stockley, P.G.|
|Subjects:||Q Science > QH Natural history > QH345 Biochemistry|
|College/School:||College of Science and Engineering > School of Chemistry|
|Journal Name:||Febs Letters|