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A novel conotoxin, qc16a, with a unique cysteine framework and folding |
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| Authors: | Ye Mingyu Hong Jing Zhou Mi Huang Lijun Shao Xiaoxia Yang Youshan Sigworth Fred J Chi Chengwu Lin Donghai Wang Chunguang |
| Affiliation: | a Institute of Protein Research, Tongji University, 1239 Siping Road, Shanghai 200092, China b The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China c Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA d College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, China e State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China |
| Abstract: | A novel conotoxin, qc16a, was identified from the venom of vermivorous Conus quercinus. qc16a has only 11 amino acid residues, DCQPCGHNVCC, with a unique cysteine pattern. Its disulfide connectivity was determined to be I-IV, II-III. The NMR structure shows that qc16a adopts a ribbon conformation with a simple beta-turn motif formed by residues Gly6, His7 and Asn8. qc16a causes depression symptom in mice when injected intracranially. Point mutation results showed that Asp1, His7 and Asn8 are all essential for the activity of qc16a. Electrophysiologically, qc16a has no strong effect on the whole-cell currents of neurons and the currents of Drosophila Shaker channels, human BK channels and NaV1.7 channels. Its specific target still remains to be identified. |
| Keywords: | Conotoxin Conus quercinus Disulfide connectivity Mutation NMR Electrophysiology |
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