Mechanically manipulating the DNA threading intercalation rate.
The dumbbell shaped binuclear ruthenium complex DeltaDelta-P requires transiently melted DNA in order to thread through the DNA bases and intercalate DNA. Because such fluctuations are rare at room temperature, the binding rates are extremely low in bulk experiments. Here, single DNA molecule stretching is used to lower the barrier to DNA melting, resulting in direct mechanical manipulation of the barrier to DNA binding by the ligand. The rate of DNA threading depends exponentially on force, consistent with theoretical predictions. From the observed force dependence of the binding rate, we demonstrate that only one base pair must be transiently melted for DNA threading to occur.
Paramanathan
Thayaparan
T
Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA.
Westerlund
Fredrik
F
McCauley
Micah J
MJ
Rouzina
Ioulia
I
Lincoln
Per
P
Williams
Mark C
MC
D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D052898:Optical Tweezers; D009942:Organometallic Compounds / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013997:Time Factors
D009942:Organometallic Compounds; D010619:Phenazines; C443808:dipyrido(3,2-a-2',3'-c)phenazine; D012428:Ruthenium; D004247:DNA