The effect of the superhelicity on the double helix twist angle in DNA.
AUTOR(ES)
Belintsev, B N
RESUMO
An attempt to estimate the relative contributions of twisting and bending to the free energy of superhelix formation from the relaxed DNA is undertaken. The extent of teritiary ordering (number of DNA axis turns tau) and that of secondary ordering (duplex twist angle beta) have been taken as thermodynamical parameters, which characterize the state of the supercoild DNA at the fixed linking number (Lk) value. Such a thermodynamical approach implies the phenomenological parameters of rigidities of twisting and supercoiling (Gbeta, Gtau). Gtau/Gbeta ratio is estimated from the presented experimental data on the winding of the double helix upon increasing the ionic strength when twist alterations are followed by circular dichroism method. The adequacy of such interpretation of CD spectra changes are discussed. The values of Gtau and Gbeta are estimated to be of the same order of magnitude.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=327746Documentos Relacionados
- DNA double helix promotes a linkage isomerization reaction in trans-diamminedichloroplatinum(II)-modified DNA.
- Effect of Circularity and Superhelicity on Transcription from Bacteriophage λ DNA
- Effect of a single 3'-methylene phosphonate linkage on the conformation of an A-DNA octamer double helix.
- On the origin of tertiary turns in covalently closed double-stranded cyclic DNA.
- A molecular mechanical model to predict the helix twist angles of B-DNA.
