title: Mechanistic insight into the structure and dynamics of entangled and hydrated λ-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 λ-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 λ-phage DNA molecule. We also observed that in 41.6% (gm water/gm DNA) hydrated state, λ-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 λ-phage DNA are distinctively different from the behavior of the corresponding unentangled DNA with open cohesive ends, which is reminiscent with our experimental observation.
authors.affiliation: Saroj Mohan Institute of Technology, West Bengal, India.
authors.forename: Sandipan
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Takashi
authors.initials: T
authors.lastname: Uematsu
authors.forename: Christer
authors.initials: C
authors.lastname: Svanberg
authors.forename: Per
authors.initials: P
authors.lastname: Jacobsson
authors.forename: Jan
authors.initials: J
authors.lastname: Swenson
authors.forename: Michael
authors.initials: M
authors.lastname: Zäch
authors.forename: Rajendar
authors.initials: R
authors.lastname: Trehan
authors.forename: George
authors.initials: G
authors.lastname: Armstrong
authors.forename: Bidisha
authors.initials: B
authors.lastname: Sengupta
mesh_terms: D010582:Bacteriophage lambda / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry*; D057446:Hydrodynamics; D009690:Nucleic Acid Conformation; D014867:Water / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D014867:Water