Sr2+ facilitates intermolecular G-quadruplex formation of telomeric sequences.

摘要: Electrophoretic and spectroscopic studies were made with the telomere-related sequences d(G4T2G4T2G4T2G4) (T2) d(G4T4G4T4G4T4G4) (T4) in presence of Na+, K+, Sr2+. evidence indicates that these two oligomers exist multiconformational states solutions. A band identified as intermolecular (tetramolecular) G-quadruplex is apparent both T2 T4, whereas a intramolecular (monomeric) G-quartet only evident T4. The remaining electrophoretic bands exhibit mobilities intermediate extremes are those hairpin-related duplexes tetraplexes. In millimolar concentrations Sr2+ subsequent thermal treatment, intensity corresponding to attributable dramatically enhanced while mobility greatly reduced. Similar but less dramatic enhancement quadruplex also observed Although effects can be induced by orders magnitude higher needed. band, T4 not T2, appears relatively insensitive type cation present solution. These results demonstrate K+ facilitate G-tetraplex formation, divalent being much more effective. Comparison CD spectral characteristics suggests correlated positive maximum at 265 nm.(ABSTRACT TRUNCATED AT 250 WORDS)