The allosteric modulation effects of doxycycline, minocycline, and their derivatives on the neuropeptide receptor PAC1-R  

作　　者：Suqin Song Like Wang Junfeng Li Xiaoling Huang Rongjie Yu 

机构地区：[1]Institute of Biomedicine,School of Life Science and Technology,Jinan University,Guangzhou 510683,China [2]National Engineering Research Center of Genetic Medicine,Jinan University,Guangzhou 510665,China

出　　处：《Acta Biochimica et Biophysica Sinica》2019年第6期627-637,共11页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the grants from the National Natural Science Foundation of China (Nos.31100545 and 31670848);the Natural Science Foundation of Guangdong Province (No.2016A030313087).

摘　　要：Class B G-protein coupled receptors (GPCR) PAC1-R is a neuropeptide pituitary adenylate cyclase activating polypeptide(PACAP)-preferring receptor that mediates the effective neuroprotective activity.Based on our previous data showing that doxycycline and minocycline work as the positive allosteric modulator (PAM) of RAC1-R,we used computer molecular docking and isothermal titration calorimetry assay to further determine the bindings of doxycycline/minocycline's derivatives including tetracycline/tigecycline with the N-terminal extracellular domain of PAC1-R (PAC1-EC1).Then the cAMP assay combined with the PAC1-R natural agonist PACAP27 was used to confirm the possible PAM roles of the small-molecule antibiotics. The results showed that tetracycline/tigecycline had significant lower affinity to PAC1-EC1 than doxycycline/minocycline, which was con sistent with their no n-positive allosteric modulation activity on PAC1-R.Furthermore, by comparing the key residues contributing to the PAM binding with the predicted allosteric site in PAC1-EC1,we characterized four motifs contributing to PAM binding in PAC1-EC1.The site-directed mutation results showed that ASN60 played the most important role in the PAM binding of the small-molecule antibiotics, while ASP116 played a sensitive marginal role in the PAM binding.These results not only help to explain the clinical and experimental neuroprotective effects of doxycycline/minocycline, but also help to characterize the PAM binding site in PAC1-EC1,which will promote the screening and characterization of novel small-molecule PAMs targeting PAC1-EC1 with drug development potency in nerve system disease.

关 键 词：pituitary ADENYLATE cyclase-activating polypeptide G-PROTEIN coupled RECEPTOR PAC1-R allosteric modulator DOXYCYCLINE MINOCYCLINE N-terminal extra cellular domain 

分 类 号：Q[生物学]