title: Structural and Functional Characterization of a Novel α-Conotoxin Mr1.7 from Conus marmoreus Targeting Neuronal nAChR α3β2, α9α10 and α6/α3β2β3 Subtypes.
abstract: In the present study, we synthesized and, structurally and functionally characterized a novel α4/7-conotoxin Mr1.7 (PECCTHPACHVSHPELC-NH2), which was previously identified by cDNA libraries from Conus marmoreus in our lab. The NMR solution structure showed that Mr1.7 contained a 310-helix from residues Pro7 to His10 and a type I β-turn from residues Pro14 to Cys17. Electrophysiological results showed that Mr1.7 selectively inhibited the α3β2, α9α10 and α6/α3β2β3 neuronal nicotinic acetylcholine receptors (nAChRs) with an IC50 of 53.1 nM, 185.7 nM and 284.2 nM, respectively, but showed no inhibitory activity on other nAChR subtypes. Further structure-activity studies of Mr1.7 demonstrated that the PE residues at the N-terminal sequence of Mr1.7 were important for modulating its selectivity, and the replacement of Glu2 by Ala resulted in a significant increase in potency and selectivity to the α3β2 nAChR. Furthermore, the substitution of Ser12 with Asn in the loop2 significantly increased the binding of Mr1.7 to α3β2, α3β4, α2β4 and α7 nAChR subtypes. Taken together, this work expanded our knowledge of selectivity and provided a new way to improve the potency and selectivity of inhibitors for nAChR subtypes.
authors.affiliation: Beijing Institute of Biotechnology, Beijing 100071, China. crosswang@gmail.com.
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing 100872, China. zhaoc271@ruc.edu.cn.
authors.forename: Cong
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Beijing Institute of Biotechnology, Beijing 100071, China. liuzhuguo@126.com.
authors.forename: Zhuguo
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing 100872, China. xuesong_wang@ruc.edu.cn.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Beijing Institute of Biotechnology, Beijing 100071, China. liuna1719@126.com.
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing 100872, China. whdu@chem.ruc.edu.cn.
authors.forename: Weihong
authors.initials: W
authors.lastname: Du
authors.affiliation: Beijing Institute of Biotechnology, Beijing 100071, China. qy_dai@yahoo.com.
authors.forename: Qiuyun
authors.initials: Q
authors.lastname: Dai
mesh_terms: D000818:Animals; D020916:Conotoxins / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D052078:Conus Snail / Q000737:chemistry; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D018733:Nicotinic Antagonists / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D020916:Conotoxins; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic
keywords: Conus marmoreus; N-terminal sequence; neuronal nicotinic acetylcholine receptor; selectivity; structure-activity relationship; α-conotoxin Mr1.7