Lin, C.-M.; Usama, S.M.; Burgess, K. Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes. Molecules2018, 23, 2900.
Lin, C.-M.; Usama, S.M.; Burgess, K. Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes. Molecules 2018, 23, 2900.
Abstract
Convenient labeling of proteins is important for observing its function under physiological conditions. In tissues particularly, heptamethine cyanine dyes (Cy-7) are valuable because they absorb in near infrared (NIR) region (750 – 900 nm) where light penetration is maximal. In this work, we found Cy-7 dyes with a meso-Cl functionality covalently binding to proteins with free Cys residues under physiological conditions (aqueous environments, at near neutral pH, and 37 °C). It transpired that the meso-Cl of the dye was displaced by free thiols in protein, while nucleophilic side-chains from amino acids like Tyr, Lys, and Ser did not react. This finding shows a new possibility for convenient and selective labeling of proteins with near-IR fluorescent probes.
Subject Areas
heptamethine cyanine; protein labeling; thiol labeling; cancer targeting; vimentin
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Chen-Ming Lin
