USTC/InterOperatorDistance
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| + | [[Image:USTC_DNALooping.png|thumb|400px|'''Figure 1''' Loop conformations and the in vivo free energy of DNA looping by the lac repressor. From [[USTC/InterOperatorDistance#Refereces|[5]]]]] | ||
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It has been accounted in a previous paper [[USTC/InterOperatorDistance#Refereces|[1-4]]] that different relative distance of the two operators can cause a periodic fluctuation in co-repression intensity. The reason is that when the two operators are a certain number of nucleotides apart, the Lac Repressor dimer tend to tetramerize and further lead to a partial supercoiling of the DNA, as is shown in the figure. | It has been accounted in a previous paper [[USTC/InterOperatorDistance#Refereces|[1-4]]] that different relative distance of the two operators can cause a periodic fluctuation in co-repression intensity. The reason is that when the two operators are a certain number of nucleotides apart, the Lac Repressor dimer tend to tetramerize and further lead to a partial supercoiling of the DNA, as is shown in the figure. | ||
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# Swigon, D., Coleman, B.D. & Olson, W.K. Modeling the Lac repressor-operator assembly: The influence of DNA looping on Lac repressor conformation. <i>PNAS 103</i>, 9879-9884 (2006). | # Swigon, D., Coleman, B.D. & Olson, W.K. Modeling the Lac repressor-operator assembly: The influence of DNA looping on Lac repressor conformation. <i>PNAS 103</i>, 9879-9884 (2006). | ||
# Müller, J., Oehler, S. & Müller-Hill, B. Repression of lac promoter as a function of distance, phase and quality of an auxiliary lac operator. <i>J. Mol. Bio.</i> 257, 21-9 (1996). | # Müller, J., Oehler, S. & Müller-Hill, B. Repression of lac promoter as a function of distance, phase and quality of an auxiliary lac operator. <i>J. Mol. Bio.</i> 257, 21-9 (1996). | ||
| + | # Saiz, L. & Vilar, J. M. G. (2006), DNA looping: the consequences and its control., <i>Curr Opin Struct Biol</i> 16(3), 344--350. | ||
Revision as of 13:19, 24 October 2007
It has been accounted in a previous paper [1-4] that different relative distance of the two operators can cause a periodic fluctuation in co-repression intensity. The reason is that when the two operators are a certain number of nucleotides apart, the Lac Repressor dimer tend to tetramerize and further lead to a partial supercoiling of the DNA, as is shown in the figure.
Such a partial supercoiling will hinder the binding of the RNA Polymerase to DNA, thus practicing a much stronger repression than a single repressor does. Since the partial supercoiling forms in periodicity according to the different relative distance of the two operators, the co-repression intensity there-caused presents periodicity as well.
References
- Y Flashner and J D Gralla, Dual Mechanism of Repression at a Distance in the lac Operon. PNAS. 1988 Dec;85(23):8968–8972.
- Saiz, L., Rubi, J.M. & Vilar, J.M.G. Inferring the in vivo looping properties of DNA. PNAS. 102, 17642-5 (2005).
- Swigon, D., Coleman, B.D. & Olson, W.K. Modeling the Lac repressor-operator assembly: The influence of DNA looping on Lac repressor conformation. PNAS 103, 9879-9884 (2006).
- Müller, J., Oehler, S. & Müller-Hill, B. Repression of lac promoter as a function of distance, phase and quality of an auxiliary lac operator. J. Mol. Bio. 257, 21-9 (1996).
- Saiz, L. & Vilar, J. M. G. (2006), DNA looping: the consequences and its control., Curr Opin Struct Biol 16(3), 344--350.
