Synthesis and characterization of a small, membrane-permeant, caspase-activatable far-red fluorescent peptide for imaging apoptosis.
To image apoptosis in vivo with a small, membrane-permeant probe, TcapQ(647) was synthesized comprising a Tat-peptide-based permeation peptide sequence, an effector caspase recognition sequence, DEVD, and a flanking optically activatable pair comprising a far-red quencher, QSY 21, and a fluorophore, Alexa Fluor 647. Under baseline conditions, high quenching efficiencies were observed resulting in low background fluorescence. Upon exposure to executioner caspases, TcapQ(647) was specifically cleaved, thereby releasing the fluorophore from the quencher and enabling imaging of apoptosis.
Bullok
Kristin
K
Molecular Imaging Center, Mallinckrodt Institute of Radiology, St. Louis, Missouri 63110, USA.
Piwnica-Worms
David
D
D017209:Apoptosis; D020169:Caspases / Q000737:chemistry / Q000378:metabolism*; D002463:Cell Membrane Permeability; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D019169:Jurkat Cells; D007624:KB Cells; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics
D005456:Fluorescent Dyes; D009842:Oligopeptides; D010455:Peptides; C519706:TcapQ647 peptide; D020169:Caspases