title: Seta-633 - a NIR fluorescence lifetime label for low-molecular-weight analytes.
abstract: We describe the photophysical properties of Seta-633, a commercially available near-infrared (NIR) dye, and its use as a fluorescent label to study the interaction between low-molecular-weight analytes and proteins using fluorescence lifetime as the readout parameter. In a model assay, we demonstrate that a biotinylated Seta-633 tracer binds to antibiotin with high specificity. Importantly, the lifetime of Seta-633-biotin increases about 1.8-fold upon binding to a specific antibody (antibiotin, MW = 160 kDa), while the titration with bovine serum albumin (BSA) or nonspecific antibody does not result in a noticeable change in lifetime. This behavior is contrary to that of fluorescent tracers like Cy5 or Alexa 647, which typically exhibit much smaller lifetime changes upon binding to antibodies.
authors.affiliation: SSI Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov 61001, Ukraine.
authors.forename: Yevgen A
authors.initials: YA
authors.lastname: Povrozin
authors.forename: Olga S
authors.initials: OS
authors.lastname: Kolosova
authors.forename: Olena M
authors.initials: OM
authors.lastname: Obukhova
authors.forename: Anatoliy L
authors.initials: AL
authors.lastname: Tatarets
authors.forename: Vadim I
authors.initials: VI
authors.lastname: Sidorov
authors.forename: Ewald A
authors.initials: EA
authors.lastname: Terpetschnig
authors.forename: Leonid D
authors.initials: LD
authors.lastname: Patsenker
mesh_terms: D000906:Antibodies / Q000276:immunology; D001710:Biotin / Q000276:immunology; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006207:Half-Life; D007259:Infrared Rays; D011506:Proteins / Q000737:chemistry*
chemical_list: D000906:Antibodies; D005456:Fluorescent Dyes; D011506:Proteins; D001710:Biotin