Patent ID: 7176037

Claim:
A method of detecting the location or environment of a cellular protein within a living cell which comprises: a. introducing a biosensor into the living cell wherein the biosensor binds to a tag on the cellular protein; and b. detecting the location or environment of a functional molecule on the biosensor within the living cell; wherein said tag is a peptide segment that has been fused to the cellular protein and said biosensor comprises the peptide conjugate of formula (III) or (IV): wherein R 6 is a peptide, a polypeptide or an antibody; X is a direct bond or a linking group; R 7 is hydrogen, (C 1 –C 6 )alkyl, an amino protecting group, or a radical comprising one or more aminooxy groups; Y is a direct bond or a linking group; Z is a linking group, or Z is a direct single bond or a double bond between N and D; and D is a functional molecule of the formula: wherein: each m is separately an integer ranging from 1–3; n is an integer ranging from 0 to 5; R 8 , R 11 and R 12 are separately CO, SO 2 , C═C(CN) 2 , S, O or C(CH 3 ) 2 ; each R 13 is alkyl, branched alkyl or heterocyclic ring derivatized with charged groups to enhance water solubility and enhance photostability; each R 9 and R 10 is separately an alkyl chain derivatized with charged groups to enhance water solubility or with reactive groups for conjugation to other molecules; provided that when D is a peptide, N and D are not linked through a —C═N—O—CH 2 —C(═O)— linkage in the backbone of the peptide conjugate.