B-S Transition in Short Oligonucleotides

@article{citeulike:1648664, abstract = {Stretching experiments with long double-stranded DNA molecules in physiological ambient revealed a force-induced transition at a force of 65 pN. During this transition between B-DNA and highly overstretched S-DNA the DNA lengthens by a factor of 1.7 of its B-form contour length. Here, we report the occurrence of this so-called B-S transition in short duplexes consisting of 30 basepairs. We employed atomic-force-microscope-based single molecule force spectroscopy to explore the unbinding mechanism of two short duplexes containing 30 or 20 basepairs by pulling at the opposite 5' termini. For a 30-basepair-long DNA duplex the B-S transition is expected to cause a length increase of 6.3 nm and should therefore be detectable. Indeed 30\% of the measured force-extension curves exhibit a region of constant force (plateau) at 65 pN, which corresponds to the B-S transition. The observed plateaus show a length between 3 and 7 nm. This plateau length distribution indicates that the dissociation of a 30-basepair duplex mainly occurs during the B-S transition. In contrast, the measured force-extension curves for a 20-basepair DNA duplex exhibited rupture forces below 65 pN and did not show any evidence of a B-S transition. 10.1529/biophysj.107.106112}, author = {Morfill, Julia and Kuhner, Ferdinand and Blank, Kerstin and Lugmaier, Robert A. and Sedlmair, Julia and Gaub, Hermann E. }, citeulike-article-id = {1648664}, doi = {10.1529/biophysj.107.106112}, journal = {Biophys. J.}, keywords = {afm, biophysics, dna, dynamic, force, overstretching, spectroscopy}, month = {October}, number = {7}, pages = {2400--2409}, posted-at = {2007-09-12 18:26:43}, priority = {4}, title = {B-S Transition in Short Oligonucleotides}, url = {http://dx.doi.org/10.1529/biophysj.107.106112}, volume = {93}, year = {2007} }

TY - JOUR ID - citeulike:1648664 L3 - citeulike-article-id:1648664 TI - B-S Transition in Short Oligonucleotides JF - Biophys. J. VL - 93 IS - 7 SP - 2400 EP - 2409 N2 - Stretching experiments with long double-stranded DNA molecules in physiological ambient revealed a force-induced transition at a force of 65 pN. During this transition between B-DNA and highly overstretched S-DNA the DNA lengthens by a factor of 1.7 of its B-form contour length. Here, we report the occurrence of this so-called B-S transition in short duplexes consisting of 30 basepairs. We employed atomic-force-microscope-based single molecule force spectroscopy to explore the unbinding mechanism of two short duplexes containing 30 or 20 basepairs by pulling at the opposite 5' termini. For a 30-basepair-long DNA duplex the B-S transition is expected to cause a length increase of 6.3 nm and should therefore be detectable. Indeed 30% of the measured force-extension curves exhibit a region of constant force (plateau) at 65 pN, which corresponds to the B-S transition. The observed plateaus show a length between 3 and 7 nm. This plateau length distribution indicates that the dissociation of a 30-basepair duplex mainly occurs during the B-S transition. In contrast, the measured force-extension curves for a 20-basepair DNA duplex exhibited rupture forces below 65 pN and did not show any evidence of a B-S transition. 10.1529/biophysj.107.106112 KW - afm KW - biophysics KW - dna KW - dynamic KW - force KW - overstretching KW - spectroscopy AU - Morfill, Julia AU - Kuhner, Ferdinand AU - Blank, Kerstin AU - Lugmaier, Robert AU - Sedlmair, Julia AU - Gaub, Hermann PY - 2007/10/01/ UR - http://dx.doi.org/10.1529/biophysj.107.106112 ER -