Facile synthesis of thiol-reactive Cy3 and Cy5 derivatives with enhanced water solubility.
The cyanine dyes Cy3 and Cy5 have proven valuable in numerous applications involving conjugation with proteins. Practical syntheses of lysine-selective, succinimidyl ester derivatives of these dyes have been published, and succinimidyl esters are commercially available. However, the published syntheses of cysteine-selective derivatives produce relatively low yields from expensive starting materials, or produce molecules with marginal water solubility for protein labeling. We report here facile syntheses (four steps, >50% overall yield) of iodoacetamide, sulfhydryl-reactive derivatives of the Cy3 and Cy5 fluorophores. These novel derivatives have good water solubility (>2.5 mM) and bear only one reactive side chain, reducing possible protein cross-linking encountered with previous derivatives.
Toutchkine
Alexei
A
Department of Cell Biology, Scripps Research Institute, 10550, N. Torrey Pines Road, BCC162, La Jolla, California 92037, USA.
Nalbant
Perihan
P
Hahn
Klaus M
KM
D002232:Carbocyanines / Q000138:chemical synthesis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D007460:Iodoacetamide / Q000737:chemistry* / Q000378:metabolism; D012995:Solubility; D014867:Water / Q000737:chemistry
D002232:Carbocyanines; D005456:Fluorescent Dyes; C089187:cyanine dye 3; C085321:cyanine dye 5; D014867:Water; D007460:Iodoacetamide