Mechanistic insight into the structure and dynamics of entangled and hydrated ?-phage DNA.

ABSTRACT: Intrinsic dynamics of DNA plays a crucial role in DNA-protein interactions and has been emphasized as a possible key component for in vivo chromatin organization. We have prepared an entangled DNA microtube above the overlap concentration by exploiting the complementary cohesive ends of ?-phage DNA, which is confirmed by atomic force microscopy and agarose gel electrophoresis. Photon correlation spectroscopy further confirmed that the entangled solutions are found to exhibit the classical hydrodynamics of a single chain segment on length scales smaller than the hydrodynamic length scale of single ?-phage DNA molecule. We also observed that in 41.6% (gm water/gm DNA) hydrated state, ?-phage DNA exhibits a dynamic transition temperature (T(dt)) at 187 K and a crossover temperature (T(c)) at 246 K. Computational insight reveals that the observed structure and dynamics of entangled ?-phage DNA are distinctively different from the behavior of the corresponding unentangled DNA with open cohesive ends, which is reminiscent with our experimental observation.

SUBMITTER: Chakraborty S 

PROVIDER: S-EPMC3391602 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature