Stretching chimeric DNA: a test for the putative S-form
2008 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 129, no 20Article in journal (Refereed) Published
Double-stranded DNA "overstretches" at a pulling force of about 65 pN, increasing in length by a factor of 1.7. The nature of the overstretched state is unknown, despite its considerable importance for DNA's biological function and technological application. Overstretching is thought by some to be a force-induced denaturation and by others to consist of a transition to an elongated, hybridized state called S-DNA. Within a statistical mechanical model, we consider the effect upon overstretching of extreme sequence heterogeneity. "Chimeric" sequences possessing halves of markedly different AT composition elongate under fixed external conditions via distinct, spatially segregated transitions. The corresponding force-extension data vary with pulling rate in a manner that depends qualitatively and strikingly upon whether the hybridized S-form is accessible. This observation implies a test for S-DNA that could be performed in experiment.
Place, publisher, year, edition, pages
2008. Vol. 129, no 20
DNA, molecular biophysics, statistical mechanics
IdentifiersURN: urn:nbn:se:kth:diva-79161DOI: 10.1063/1.3009266ISI: 000262607100037OAI: oai:DiVA.org:kth-79161DiVA: diva2:495180
QC 201202092012-02-082012-02-082012-02-09Bibliographically approved