Int. J. Mol. Sci. 2014, 15(9), 15090-15108; doi:10.3390/ijms150915090
Article

What Controls DNA Looping?

1email, 1email, 1email, 1email and 1,2,* email
Received: 11 July 2014; in revised form: 11 August 2014 / Accepted: 19 August 2014 / Published: 27 August 2014
(This article belongs to the Special Issue Identification and Roles of the Structure of DNA)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The looping of DNA provides a means of communication between sequentially distant genomic sites that operate in tandem to express, copy, and repair the information encoded in the DNA base sequence. The short loops implicated in the expression of bacterial genes suggest that molecular factors other than the naturally stiff double helix are involved in bringing the interacting sites into close spatial proximity. New computational techniques that take direct account of the three-dimensional structures and fluctuations of protein and DNA allow us to examine the likely means of enhancing such communication. Here, we describe the application of these approaches to the looping of a 92 base-pair DNA segment between the headpieces of the tetrameric Escherichia coli Lac repressor protein. The distortions of the double helix induced by a second protein—the nonspecific nucleoid protein HU—increase the computed likelihood of looping by several orders of magnitude over that of DNA alone. Large-scale deformations of the repressor, sequence-dependent features in the DNA loop, and deformability of the DNA operators also enhance looping, although to lesser degrees. The correspondence between the predicted looping propensities and the ease of looping derived from gene-expression and single-molecule measurements lends credence to the derived structural picture.
Keywords: DNA looping; optimization; J factor; lac operon; Monte Carlo simulations
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MDPI and ACS Style

Perez, P.J.; Clauvelin, N.; Grosner, M.A.; Colasanti, A.V.; Olson, W.K. What Controls DNA Looping? Int. J. Mol. Sci. 2014, 15, 15090-15108.

AMA Style

Perez PJ, Clauvelin N, Grosner MA, Colasanti AV, Olson WK. What Controls DNA Looping? International Journal of Molecular Sciences. 2014; 15(9):15090-15108.

Chicago/Turabian Style

Perez, Pamela J.; Clauvelin, Nicolas; Grosner, Michael A.; Colasanti, Andrew V.; Olson, Wilma K. 2014. "What Controls DNA Looping?" Int. J. Mol. Sci. 15, no. 9: 15090-15108.

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