Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes
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 the 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 NIR fluorescent probes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 07, 2018
- Source ID
- 10.3390/molecules23112900
Entities
People
- Chen-Ming Lin
- Kevin S Burgess
- Syed Usama
Organizations
- Cancer Prevention and Research Institute of Texas
- National Science Foundation
- Robert A. Welch Foundation
- United States Department of Defense