title: Intramolecular i-motif structure at acidic pH for progressive myoclonus epilepsy (EPM1) repeat d(CCCCGCCCCGCG)n.
abstract: The most common mutation associated with Progressive Myoclonus Epilepsy (EPM1) of Unverricht-Lundberg type is the expansion of a dodecamer repeat, d(CCCCGCCCCGCG)n. We show that the C-rich strand of this repeat (2-3 copies) forms intercalated i-motif structure at acidic pH as judged by CD spectroscopy and anomalous gel electrophoretic mobility. The stability of the structure increases with the increase in the length of the repeat. Transient formation of stable, folded back structure like i-motif could play an important role in the mechanism of expansion of this repeat.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
authors.forename: S S
authors.initials: SS
authors.lastname: Pataskar
authors.forename: D
authors.initials: D
authors.lastname: Dash
authors.forename: S K
authors.initials: SK
authors.lastname: Brahmachari
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D055313:Cystatin B; D015891:Cystatins / Q000235:genetics*; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D018598:Minisatellite Repeats; D009154:Mutation; D020191:Myoclonic Epilepsies, Progressive / Q000235:genetics*; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics; D013056:Spectrophotometry, Ultraviolet
chemical_list: C524994:CSTB protein, human; D015891:Cystatins; D009838:Oligodeoxyribonucleotides; D055313:Cystatin B; D004247:DNA