Synchrotron radiation small angle scattering studies of d(TTAGGG) 4 oligomer in solution

Abstract

Telomeric DNA sequences play a crucial role in maintaining chromosome stability and integrity. In human chromosomes telomeres are composed of tandem (TTAGGG) n repeats. The structural parameters and low-resolution structure of a synthetic d(TTAGGG) 4 oligomer in solution has been studied in the absence and in the presence of potassium cations, with the use of the small angle scattering of synchrotron radiation. The radii of gyration R G, calculated for d(TTAGGG) 4 oligomer (in 10 mM Tris/HCl pH 7.3) was 1.42 nm, while R G, (in 10 mM Tris/HCl pH 7.3; 0.1 mM KCl) was 1.32 nm. The pair distance distribution function, P( r), yielded a maximum dimension of 4.55and 4.35 nm for solutions in the absence and the presence of potassium cations. On the basis of SAXS data, the low-resolution structure in solution has been reconstructed using ab inito methods.