Design and synthesis of peptide-drug conjugates and fluorescent probe based on α-conotoxin ArIBV11L,V16D

α-Conotoxin ArIBV11L,V16D is currently the most optimal selective inhibitor of α7 nicotinic acetylcholine receptor (nAChR) known. In order to explore chemical modification methods and enrich its application in targeting nAChR, this study utilized the linker to covalently connect camptothecin and 7-amino-4-methylcoumarin to the 2,4 disulfide bond of ArIBV11L,V16D. Therefore, two peptide-drug conjugates (PDCs), ArIBV11L,V16D-5 and ArIBV11L,V16D-6, and one fluorescent-labeled peptide, ArIBV11L,V16D-7 were constructed. Cytotoxicity evaluation showed that the IC₅₀ values against non-small cell lung cancer cell line A549 of the two PDCs were respectively 1.3 and 4.1 times of camptothecin, indicating slight reduction in activity at the cellular level which was related to the linker structure. Fluorescence spectrum scanning revealed that the excitation and emission wavelength of the fluorescent-labeled peptide were 340 nm and 403 nm respectively, and the fluorescence features of 7-amino-4-methylcoumarin as a marker were retained without fluorescence quenching. This modification strategy laid a solid foundation for the further application of α-conotoxin ArIBV11L,V16D in PDCs and fluorescent probes.