TY - JOUR
T1 - DNA Twist Stability Changes with Magnesium(2+) Concentration
AU - Broekmans, O.D.
AU - King, G.A.
AU - Stephens, G.J.
AU - Wuite, G.J.L.
PY - 2016
Y1 - 2016
N2 - To understand DNA elasticity at high forces (F>30 pN), its helical nature must be taken into account, as a coupling between twist and stretch. The prevailing model, the wormlike chain, was previously extended to include this twist-stretch coupling. Motivated by DNA's charged nature, and the known effects of ionic charges on its elasticity, we set out to systematically measure the impact of buffer ionic conditions on twist-stretch coupling. After developing a robust fitting approach, we show, using our new data set, that DNA's helical twist is stabilized at high concentrations of the magnesium divalent cation. DNA's persistence length and stretch modulus are, on the other hand, relatively insensitive to the applied range of ionic strengths.
AB - To understand DNA elasticity at high forces (F>30 pN), its helical nature must be taken into account, as a coupling between twist and stretch. The prevailing model, the wormlike chain, was previously extended to include this twist-stretch coupling. Motivated by DNA's charged nature, and the known effects of ionic charges on its elasticity, we set out to systematically measure the impact of buffer ionic conditions on twist-stretch coupling. After developing a robust fitting approach, we show, using our new data set, that DNA's helical twist is stabilized at high concentrations of the magnesium divalent cation. DNA's persistence length and stretch modulus are, on the other hand, relatively insensitive to the applied range of ionic strengths.
U2 - 10.1103/PhysRevLett.116.258102
DO - 10.1103/PhysRevLett.116.258102
M3 - Article
SN - 0031-9007
VL - 116
JO - Physical Review Letters
JF - Physical Review Letters
IS - 25
M1 - 258102
ER -