Site-specific modification of proteins with synthetic fluorescent tag effectively improves the resolution of imaging, and such a labeling method with negligible three-dimensional structural perturbations and minimal impact on the biological functions of proteins is of high interest to dissect the high-resolution activities of biomolecules in complex systems. To this end, several non-emissive iridium(III) complexes [Ir(C-N)2 (H2 O)2 ]+ OTF- (C-N denotes various cyclometalated ligands) were designed and synthesized. These complexes were tested for attaching a protein by coordinating to H/X (HisMet, HisHis, and HisCys) that are separated by i and i+4 in α-helix. Replacement of the two labile water ligands in the iridium(III) complex by a protein HisHis pair increases the luminescent intensity up to over 100 folds. This labeling approach has been demonstrated in a highly specific and efficient manner in a number of proteins, and it is also feasible for labeling target proteins in cell lysates. © 2024 Wiley-VCH GmbH.
Shu-Li Guo, Yu-Hao Xiao, Bin-Bin Pan, Xun-Cheng Su. Site-Specific Anchoring a Luminescent Tag in a Protein with Non-Emissive Iridium(III) Complex. Chembiochem : a European journal of chemical biology. 2024 Feb 16;25(4):e202300798
PMID: 38169080
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