Sensing of biomolecules and label-free discrimination of DNA containing a triple T–C/T–G mismatch pair with a fluorescence light-up probe, triazolylpyrene (TNDMBPy)

Uracil-amino acid as a scaffold for β-sheet peptidomimetics: Study of photophysics and interaction with BSA protein

We report herein the uracil-di-aza-amino acid (U^rAA) as a new family of molecular scaffold to induce β-hairpin structure with H-bonded β-sheet conformation in a short peptide. This has been demonstrated in two conceptual fluorescent pentapeptides wherein triazolylpyrenyl alanine and/or triazolylmethoxynapthyl alanine (^TPyAla_Do and/or ^TMNapAla_Do) are embedded into two arms of the uracil-amino acid via an intervening leucine. Conformational analysis by CD, IR, variable temperature and 2D NMR spectroscopy reveals the β-hairpin structures for both the peptides. Study of photophysical property reveals that the pentapeptide containing fluorescent triazolyl unnatural amino acids ^TMNapAla_Do and ^TPyAla_Do at the two termini exhibits dual path entry to exciplex emission-either via FRET from ^TMNapAla_Do to ^TPyAla_Do or via direct excitation of a FRET acceptor, ^TPyAla_Do. The other pentapeptide with ^TPyAla_Do/^TPyAla_Do pair shows excimer emission. Furthermore, both the peptides maintaining their fundamental photophysics are found to interact with BSA as only a test biomolecule.

Tetrazolylpyrene unnatural nucleoside as a human telomeric multimeric G-quadruplex selective switch-on fluorescent sensor

Specific sensing of dimeric H45 G-quadruplex DNA using a fluorescence light-up probe, tetrazolylpyrene nucleoside (^TzPyB_Do), is reported.

Trichromophoric pentapeptide: impact of β-sheet conformation on dual path to excimer emission and sensing of BSA

We established dual mechanisms for excimer emission-either via FRET or direct excitation of a FRET acceptor- in a conceptually novel trichromophoric pentapeptide which serves as an effective fluorescence light-up probe for protein–peptide interaction.

Donor/acceptor chromophores-decorated triazolyl unnatural nucleosides: synthesis, photophysical properties and study of interaction with BSA

We report the syntheses and photophysical properties of some triazolyl donor/acceptor unnatural nucleosides and studies on the interaction of one of the fluorescent nucleosides with BSA.