A novel 4/6-type alpha-conotoxin ViIA selectively inhibits nAchR α3β2 subtype.
Conotoxins (CTxs) are typically small peptides composed of 12-50 amino acid residues with 2-5 disulfide bridges. Most of them potently and selectively target a wide variety of ion channels and membrane receptors. They are highly valued as neuropharmacological probes and in pharmaceutical development. In this work, a novel α4/6-CTx named ViIA (RDCCSNPPCAHNNPDC-NH2) was identified from a cDNA library of the venom ducts of Conus virgo (C. virgo). ViIA was then synthesized chemically and its disulfide connectivity was identified as 'C(1)-C(3), C(2)-C(4)'. Its molecular targets were further assessed using two-electrode voltage clamping. The results indicated that ViIA selectively inhibited nicotinic acetylcholine receptor (nAChR) α3β2 subtype with an IC50 of 845.5 nM, but did not target dorsal root ganglion sodium (Na(+))-, potassium (K(+))- or calcium (Ca(2+))-ion channels. Further structure-activity relationship analysis demonstrated that Arg(1) and His(11) but not Asp(2) were the functional residues. To the best of our knowledge, ViIA is the first 4/6 α-CTx that selectively inhibits nAChR α3β2 subtype. This finding expands the knowledge of targets of α4/6-family CTxs.
Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China Beijing Institute of Biotechnology, Beijing 100071, China.
Liang
L
Li
Beijing Institute of Biotechnology, Beijing 100071, China.
Na
N
Liu
Beijing Institute of Biotechnology, Beijing 100071, China.
Rong
R
Ding
Beijing Institute of Biotechnology, Beijing 100071, China.
Shuo
S
Wang
Beijing Institute of Biotechnology, Beijing 100071, China.
Zhuguo
Z
Liu
Beijing Institute of Biotechnology, Beijing 100071, China.
Haiying
H
Li
Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China.
Xing
X
Zheng
Beijing Institute of Biotechnology, Beijing 100071, China qy_dai@yahoo.com.
Qiuyun
Q
Dai
D000109:Acetylcholine / Q000737:chemistry; D020816:Amino Acid Motifs; D000818:Animals; D020916:Conotoxins / Q000737:chemistry*; D052078:Conus Snail; D004220:Disulfides; D005786:Gene Expression Regulation; D015723:Gene Library; D020128:Inhibitory Concentration 50; D018733:Nicotinic Antagonists / Q000737:chemistry*; D009865:Oocytes / Q000166:cytology; D018408:Patch-Clamp Techniques; D051381:Rats; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014981:Xenopus
D020916:Conotoxins; D004220:Disulfides; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; C419362:nicotinic receptor alpha3beta2; D000109:Acetylcholine
ViIA; cloning; synthesis; α-conotoxin; α3β2 nAChR subtype