| 摘要 |
Tissue slices and whole organisms offer substantial challenges to fluorescence imaging. Autofluorescence and absorption via intrinsic chromophores, such as flavins, melanin, and hemoglobins, confound and degrade output from all fluorescent tags. An “optical window,” farther red than most autofluorescence sources and in a region of low hemoglobin and water absorbance, lies between 650 and 900 nm. This valley of relative optical clarity is an attractive target for fluorescence-based studies within tissues, intact organs, and living organisms. Novel fluorescent tags were developed herein, based upon a genetically targeted fluorogen activating protein and cognate fluorogenic dye that yields emission with a peak at 733 nm exclusively when complexed as a “fluoromodule”. This tool improves substantially over previously described far-red/NIR fluorescent proteins in terms of brightness, wavelength, and flexibility by leveraging the flexibility of synthetic chemistry to produce novel chromophores. |
| 主权项 |
1. A composition comprising:
a fluorogen and a cognate fluorogen-activating peptide wherein, upon binding to the fluorogen-activating peptide, the fluorogen fluoresces having an emission peak in the near infrared region, the fluorogen having the structure wherein R1, R2, R3, R4, and R5 are the same or different and are selected from H, Cl, Br, I, F, an electron donating group, or an electron withdrawing group; R5 and R6 are the same or different and are selected from the group consisting of substituents that comprise one or more of hydrogen, alkyl groups, substituted alkyl groups, esters, aryl groups, substituted aryl groups, amines, amides, sulfonated groups, carboxylated groups, multiple hydroxy groups and substituents that can conjugate the fluorogen to another chemical species; and, n is an integer from 0 to 2;
wherein the fluorogen-activating peptide is selected from the group consisting of SEQ. ID. 20, SEQ. ID. 21, and a polypeptide sequence having at least 90% sequence identity to the polypeptide of SEQ. ID. NOs. 1, 2, and 3. |
