Biophysical characterization of an ensemble of intramolecular i-motifs formed by the human c-MYC NHE III1 P1 promoter mutant sequence.

ABSTRACT: i-Motif-forming sequences are present in or near the regulatory regions of >40% of all genes, including known oncogenes. We report here the results of a biophysical characterization and computational study of an ensemble of intramolecular i-motifs that model the polypyrimidine sequence in the human c-MYC P1 promoter. Circular dichroism results demonstrate that the mutant sequence (5'-CTT TCC TAC CCTCCC TAC CCT AA-3') can adopt multiple "i-motif-like," classical i-motif, and single-stranded structures as a function of pH. The classical i-motif structures are predominant in the pH range 4.2-5.2. The "i-motif-like" and single-stranded structures are the most significant species in solution at pH higher and lower, respectively, than that range. Differential scanning calorimetry results demonst

SUBMITTER: Dettler JM 

PROVIDER: S-EPMC2905117 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature