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dc.contributor.authorKahn, Jason D.
dc.contributor.authorCheong, Raymond
dc.contributor.authorEdelman, Laurence M.
dc.contributor.authorMehta, Ruchi A.
dc.contributor.authorMorgan, Michael A.
dc.date.accessioned2006-10-11T13:28:29Z
dc.date.available2006-10-11T13:28:29Z
dc.date.issued2006-10
dc.identifier.citationhttp://www.worldscinet/brl/brl.shtmlen
dc.identifier.urihttp://hdl.handle.net/1903/3959
dc.descriptionCombined research report and review article on our work in DNA looping. Presented at the Asia and Pacific Workshop on Biological Physics, Singapore, July 2006.en
dc.description.abstractProtein-DNA loops are essential for efficient transcriptional repression and activation. The geometry and stability of the archetypal Lac repressor tetramer (LacI)-DNA loop were investigated using designed hyperstable loops containing lac operators bracketing a sequence-directed bend. Electrophoretic mobility shift assays, DNA cyclization, and bulk and single-molecule fluorescence resonance energy transfer (FRET) demonstrate that the DNA sequence controls whether the LacI-DNA loop forms a compact loop with positive writhe or an open loop with little writhe. Monte Carlo methods for simulation of DNA ring closure were extended to DNA loops, including treatment of variable protein hinge angles. The observed distribution of topoisomer products upon cyclization provides a strong constraint on possible models. The experiments and modeling imply that LacI-DNA can adopt a wide range of geometries but has a strong intrinsic preference for an open form. The flexibility of LacI helps explain in vivo observations that DNA looping is less sensitive to DNA length and shape than would be expected from the physical properties of DNA. While DNA cyclization suggests two pools of precursor loops for the 9C14 construct, single-molecule FRET demonstrates a single population. This discrepancy suggests that the LacI-DNA structure is strongly influenced by flanking DNA.en
dc.description.sponsorshipNSF, NIHen
dc.format.extent1315032 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.publisherWorld Scientific Publishing Companyen
dc.subjectLac repressoren
dc.subjectDNA topologyen
dc.subjectMonte Carlo simulationen
dc.subjectFluorescence resonance energy transferen
dc.titleFlexibility and Control of Protein-DNA Loopsen
dc.relation.isAvailableAtDigital Repository at the University of Marylanden_us
dc.relation.isAvailableAtChemistry and Biochemistry Departmenten_us
dc.relation.isAvailableAtCollege of Chemical & Life Sciencesen_us
dc.relation.isAvailableAtUniversity of Maryland (College Park, Md.)en_us


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