Separation of Trp-Arg and Arg-Trp using G-quartet-forming DNA oligonucleotides in open-tubular capillary electrochromatography.
DNA oligonucleotides that form intramolecular G-quartet structures were investigated as stationary phase reagents for separation of mixtures of the isomeric dipeptides Trp-Arg and Arg-Trp in open-tubular capillary electrochromatography (OTCEC). The oligonucleotides included a thrombin-binding aptamer that forms a biplanar G-quartet structure and an oligonucleotide that forms a 4-plane G-quartet structure. Fluorescence, circular dichroism and UV-visible absorbance spectroscopies were used in batch solution studies to indicate interactions between the dipeptides and the biplanar G-quartet structure. Results for OTCEC separations were compared with results obtained for capillary zone electrophoresis separations on a bare capillary. Temperature studies suggest that resolution is improved when the G-quartet structure is partially destabilized, but control experiments in which potassium chloride was not included in the mobile phase indicate that the G-quartet structure nevertheless plays a role in the separations.
Department of Chemistry, P.M. Gross Chemical Laboratory, Duke University, Box, 90346, Durham, NC 27708, USA.
Joseph A M
JA
Charles
Linda B
LB
McGown
D001120:Arginine; D002845:Chromatography / Q000379:methods; D004151:Dipeptides / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006151:Guanosine; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D013057:Spectrum Analysis; D014364:Tryptophan
D004151:Dipeptides; D009841:Oligonucleotides; D006151:Guanosine; D014364:Tryptophan; D001120:Arginine