Synthesis of a Peptide-Human Telomere DNA conjugate as a fluorometric imaging reagent for biological sodium ion

Abstract

A peptide-oligonucleotide conjugate (1) was synthesized by the attachment of FAM, TAMRA, and biotin moieties to a telomere DNA sequence of 5'-TAG GGT TAG GGT TAG GGT TAG GG-3'. This conjugate was induced to be an antiparallel structure in the presence of sodium ion (Na + ), whereas a hybrid one was formed under potassium ion (K + ) as a monitoring by circular dichromic spectra. The conformation change of this conjugate gave an effective FRET signal change upon the addition of NaCl, compared with the case of KCl. Under 5 mM KCl as an extracellular condition, a FRET change was observed upon addition of NaCl and quantitative FRET change was observed in 0 - 250 mM NaCl. This conjugate was immobilized on the cell surface through a sugar chain on the cell, biotinyl concanavallin A and streptavidin. This conjugate was utilized for Na + sensing based on anti-parallel tetraplex formation with Na + .