An efficient method for the site-specific ^(99m)Tc labeling of nanobody  

作　　者：Qi Luo Hannan Gao Jiyun Shi Fan Wang 

机构地区：[1]Bioland Laboratory(Guangzhou Regenerative Medicine and Health Guangdong Laboratory),Guangzhou 510005,China [2]Medical Isotopes Research Center and Department of Radiation Medicine,State Key Laboratory of Natural and Biomimetic Drugs,School of Basic Medical Sciences,Peking University,Beijing 100191,China [3]Key Laboratory of Protein and Peptide Pharmaceuticals,CAS Center for Excellence in Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,China [4]Beijing Translational Center for Biopharmaceuticals,Beijing 100101,China

出　　处：《Biophysics Reports》2021年第4期295-303,共9页生物物理学报（英文版）

基　　金：This work was supported by National Natural Science Foundation of China(81630045,81927802 and 81971676);and Emergency Key Program of Guangzhou Laboratory(EKPG21-16).

摘　　要：Recently,there has been a lot of interest by using nanobodies(heavy chain-only antibodies produced naturally from the Camelidae)as targeting molecules for molecular imaging,especially for the nuclear medicine imaging.A radiolabeled method that generates a homogeneous product is of utmost importance in radiotracer development for the nuclear medicine imaging.The conventional method for the radiolabeling of nanobodies is non-specifically,which conjugates the radioisotope chelating group to the side chain£-amine group of lysine or sulfhydryl of cysteine of nanobodies,with a shortcoming of produce of the heterogeneous radiotracer.Here we describe a method for the site-specific radioisotope ^(99m)Tc labeling of nanobodies by transpeptidase Sortase A.The radiolabeling process includes two steps:first step,NH2-GGGGK(HYNIC)-COOH peptide(GGGGK=NH2-Gly-Gly-Gly-Gly-Lys-COOH,HYNIC=6-hydrazinonicotinyl)was labeled with^(99m)Tc to obtain GGGGK-HYNIC-^(99m)Tc;second step,Sortase A catalyzes the formation of a new peptide bond between the peptide motif LPETG(NH2-Leu-Pro-Glu-Thr-Gly-COOH)expressed C-terminally on the nanobody and the N-terminal of GGGGK-HYNIC-^(99m)Tc.After a simple purification process,homogeneous single-conjugated and stable^(99m)Tc-labeled nanobodies were obtained in>50%yield.This approach demonstrates that the Sortase A-mediated conjugation is a valuable strategy for the development of site-specifically^(99m)Tc-labeled nanobodies.

关 键 词：NANOBODY Sortase A Site-specific radiolabeling ^(99m)Tc 

分 类 号：Q503[生物学—生物化学]