Cooper, A., Mcalpine, A., and Stockley, P. G. (1994) Calorimetric studies of the energetics of protein—DNA interactions in the E. coli methionine repressor (MetJ) system. FEBS Letters, 348(1), pp. 41-45. (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 (ΔH ⋍ −99 kJ•mol−1) than either MetJ:DNA or MetJ:SAM binary complexes alone (ΔH ⋍ −10 kJ•mol−1 each). The protein is also significantly more stable to unfolding (ΔTm ⋍ 5.4°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) Enlighten ID:||Cooper, Professor 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|
|Published Online:||19 October 2001|