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Titolo:
Effect of salt-dependent stiffness on the conformation of a stressed DNA loop containing initially coplanar bends
Autore:
White, JH; Lund, RA; Bauer, WR;
Indirizzi:
SUNY Stony Brook, Sch Med, Dept Microbiol, Stony Brook, NY 11794 USA SUNY Stony Brook Stony Brook NY USA 11794 biol, Stony Brook, NY 11794 USA Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90024 USA Univ Calif Los Angeles Los Angeles CA USA 90024 Los Angeles, CA 90024 USA
Titolo Testata:
BIOPOLYMERS
fascicolo: 7, volume: 49, anno: 1999,
pagine: 605 - 619
SICI:
0006-3525(199906)49:7<605:EOSSOT>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
ESCHERICHIA-COLI; TRANSCRIPTION; ACTIVATION; WRITHE; TWIST; MECHANISM; PROMOTER; SITE;
Keywords:
DNA loop; finite element analysis; bent DNA; DNA elasticity; writhe; persistence length;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Bauer, WR SUNY Stony Brook, Sch Med, Dept Microbiol, Stony Brook, NY 11794USA SUNY Stony Brook Stony Brook NY USA 11794 y Brook, NY 11794 USA
Citazione:
J.H. White et al., "Effect of salt-dependent stiffness on the conformation of a stressed DNA loop containing initially coplanar bends", BIOPOLYMERS, 49(7), 1999, pp. 605-619

Abstract

Closed DNA loops containing one or more bent regions are important structures that occur in the regulation of gene expression. We analyze the response of structures of this type to a change in applied rotation (change in linking deficiency, Delta Lk). Our results apply to a closed loop formed from an elastic rod that is intrinsically bent in N-b discrete, 20 degrees stepstip to a maximum of 240 degrees, the bent regions being initially coplanarwith the plane of the relaxed DNA loop. We determine the effect of changing the intrinsic elastic resistance of the DNA loop to bending and torsionaldeformations. This relative resistance is expressed by Poisson's ratio nu,which depends upon the ratio of bending bending stiffness to torsional rigidity. Poisson's ratio is primarily a function of salt type and concentration. We find that the tertiary structure of DNA loops changes with Delta Lk,but that the geometric response can be either of trio quite different types, depending upon the bending precise (N-b, nu) pair For combinations of N-b and nu that are above a critical curve (the Fickel curve), the response to increasing Delta Lk is nonmonotonic (NMT region): the distance between the loop closure point and its diametric opposite first decreases, then increases, as Delta Lk increases. For combinations of N-b and nu that nta below the Fickel curve (NMT region), the corresponding diameter never increases, but always decreases with increasing Delta Lk. In addition to these results, we define and implement a new measure of tertiary structure in closed DNA: the absolute writhe, AWr. (C) 1999 John Wiley & Sons, Inc.

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Documento generato il 14/07/20 alle ore 18:51:29