Results 151 to 160 of about 11,463 (183)
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Thermodynamic properties of superhelical DNAs
Biochemistry, 1975Binding isotherms of ethidium to the superhelical DNA from phage PM2, and to PM2 DNA containing -1 single-chain scission per molecule, have been determined at six temperatures from 2.5 to 50 degrees, in 3M CsCl-0.01 M Na3EDTA. Spectrophotometric measurements in both the visible and ultraviolet (uv) regions were used to obtain the binding isotherms. The
T S, Hsieh, J C, Wang
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Surface-Induced DNA Superhelicity
Biomacromolecules, 2000Certain biopolymers, such as DNA, have a double-stranded twisted structure and frequently exhibit a supercoiled conformation. Over the past decade, extensive conformational analyses of different biopolymers have been performed using atomic force microscopy.
Y S, Velichko +2 more
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Circular dichroism of superhelical DNA
Biopolymers, 1971AbstractThe circular dichroism (CD) spectra of a number of superhelical DNA's have been measured. The introduction of negative superhelical turns causes an increase in magnitude of the positive band around 280 mμ, while the trough around 250mμ is little affected.
M F, Maestre, J C, Wang
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Internal Dynamics of Superhelical DNA
Physical Review Letters, 2008We present the first data on the temporal kinetics of monomer mean square displacements in DNA circles with defined degrees of superhelicity. The segmental dynamics of specifically labeled DNA plasmids with superhelical densities between 0 and -0.016 was assessed by fluorescence correlation spectroscopy.
Roman, Shusterman +2 more
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Replication of Superhelical DNAs in Vitro
1986Publisher Summary This chapter discusses purified systems that can replicate closed-circular, double-stranded superhelical (form I) DNAs in vitro . It also discusses problems unique to the replication of DNAs under topological constraint. Studies on the reconstituted pBR322 DNA replication system are used as a guide in the chapter. Recent studies on
K J, Marians, J S, Minden, C, Parada
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Prokaryotic DNA Ligases Unwind Superhelical DNA
Biochemical and Biophysical Research Communications, 1996We have studied the effect on DNA topology of binding of prokaryotic DNA ligases (T4 and E. coli) to superhelical or nicked circular DNA. Performing topoisomerase I-mediated relaxation in the presence of increasing amounts of T4 ligase led to a shift in the topoisomer distribution to increasingly more negative values.
M, Ivanchenko +2 more
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Electrostatic effects in short superhelical DNA
Biophysical Chemistry, 1994We present Monte Carlo simulations of the equilibrium configurations of short closed circular DNA that obeys a combined elastic, hard-sphere, and electrostatic energy potential. We employ a B-spline representation to model chain configuration and simulate the effects of salt on chain folding by varying the Debye screening parameter.
M O, Fenley +3 more
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Energetics of superhelicity and of B-Z transitions in superhelical DNA
Cell Biophysics, 1987The linking difference, alpha, imposed upon a superhelically constrained DNA molecule must be partitioned between twisting and bending deformations. Transitions to alternative secondary structures can occur at susceptible sites, altering the local molecular twist by an amount delta Twtrans.
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Effect of DNA superhelicity on transcription termination
Molecular and General Genetics MGG, 1987Restriction fragments containing either leut (a rho-independent transcription termination site) and/or leut' (a rho-dependent transcription termination site) were cloned into plasmid pOL4. Treatment of plasmid-containing Escherichia coli strains with coumermycin resulted in loss of in vivo plasmid superhelicity 10 min after antibiotic addition ...
E R, Rosenthal, J M, Calvo
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