Populated intermediates in the thermal unfolding of the human telomeric quadruplex.

ABSTRACT: Thermal denaturation profiles of several model oligonucleotides of the human telomere DNA sequence including d[A(GGGTTA)(3)GGG] (Tel22) were determined using circular dichroism (CD), fluorescence of adenine → 2-aminopurine analogs, and fluorescence resonance energy transfer (FRET) to monitor the unfolding process at specific locations within the quadruplex. The resulting optical spectra vs temperature data matrices were analyzed by singular value decomposition (SVD) to ascertain the minimum number of species required to reproduce the unfolding spectral profiles. Global nonlinear least-squares fitting of the SVD amplitude vectors was used to estimate thermodynamic parameters and optical spectra of all species for a series of unfolding mechanisms that included one-, two-, and three-step sequ

SUBMITTER: Gray RD 

PROVIDER: S-EPMC3477705 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature