conformation effects of cpg methylation on single-stranded dna oligonucleotides analysis of the opioid peptide dynorphin-coding sequences构象的影响cpg甲基化在阿片肽的单链dna寡核苷酸分析dynorphin-coding序列.pdfVIP

Conformation Effects of CpG Methylation on Single- Stranded DNA Oligonucleotides: Analysis of the Opioid Peptide Dynorphin-Coding Sequences 1.¤ ¨ ¨ 2. 1 2 Malik Mumtaz Taqi , Sebastian K. T. S. Warmlander , Olga Yamskova , Fatemeh Madani , 1 2 3 4 ¨ 2 1 Igor Bazov , Jinghui Luo , Roman Zubarev , Dineke Verbeek , Astrid Graslund , Georgy Bakalkin * 1 Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden, 2 Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden, 3 Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden, 4 Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands Abstract Single-stranded DNA (ssDNA) is characterized by high conformational flexibility that allows these molecules to adopt a variety of conformations. Here we used native polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy to show that cytosine methylation at CpG sites affects the conformational flexibility of short ssDNA molecules. The CpG containing 37-nucleotide PDYN (prodynorphin) fragments were used as model molecules. The presence of secondary DNA structures was evident from differences in oligonucleotide mobilities on PAGE, from CD spectra, and from formation of A-T, G-C, and non-canonical G-T base pairs observed by NMR spectroscopy. The oligonucleotides displayed secondary structure