Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes
Department of Chemistry, Texas A & M University, Box 30012, College Station, TX 77842, USA
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Academic Editor: Maged Henary
Molecules 2018, 23(11), 2900; https://doi.org/10.3390/molecules23112900
Received: 19 October 2018
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Revised: 5 November 2018
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Accepted: 6 November 2018
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Published: 7 November 2018
(This article belongs to the Special Issue Small Molecule Near Infrared Contrast Agents: Synthesis and Applications)
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.
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MDPI and ACS Style
Lin, C.-M.; Usama, S.M.; Burgess, K. Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes. Molecules 2018, 23, 2900. https://doi.org/10.3390/molecules23112900
AMA Style
Lin C-M, Usama SM, Burgess K. Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes. Molecules. 2018; 23(11):2900. https://doi.org/10.3390/molecules23112900
Chicago/Turabian StyleLin, Chen-Ming, Syed M. Usama, and Kevin Burgess. 2018. "Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes" Molecules 23, no. 11: 2900. https://doi.org/10.3390/molecules23112900
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