A Noncompetitive Peptide Inhibitor of the Nicotinic Acetylcholine Receptor from Conus purpurascens Venom
详细信息 查看全文
- 作者：Ki-Joon Shon ; Michelle Grilley ; Richard Jacobsen ; G. Edward Cartier ; Chris Hopkins ; William R. Gray ; Maren Watkins ; David R. Hillyard ; Jean Rivier ; Josep Torres ; Doju Yoshikami ; and Baldomero M. Olive
- 刊名：Biochemistry
- 出版年：1997
- 出版时间：August 5, 1997
- 年：1997
- 卷：36
- 期：31
- 页码：9581 - 9587
- 全文大小：147K
- 年卷期：v.36,no.31(August 5, 1997)
- ISSN：1520-4995
文摘
A paralytic peptide, 
fchars/psi.gif" BORDER=0 >-conotoxin PIIIE has beenpurified and characterized from Conuspurpurascens venom. Electrophysiological studies indicatethat the peptide inhibits the nicotinicacetylcholine receptor (nAChR). However, the peptide does notblock the binding of fchars/alpha.gif" BORDER=0>-bungarotoxin, acompetitive nAChR antagonist. Thus, fchars/psi.gif" BORDER=0 >-conotoxinPIIIE appears to inhibit the receptor at a siteotherthan the acetylcholine-binding site. As ascertained by sequenceanalysis, mass spectrometry, and chemicalsynthesis, the peptide has the following covalent structure:HOOCCLYGKCRRYOGCSSASCCQR*(O = 4-trans hydroxyproline; * indicates an amidatedC-terminus). The disulfide connectivity of thetoxin is unrelated to the fchars/alpha.gif" BORDER=0>- or the fchars/alpha.gif" BORDER=0>A-conotoxins, theConus peptide families that are competitiveinhibitorsof the nAChR, but shows homology to the 
f">-conotoxins (which areNa+ channel blockers).
fchars/psi.gif" BORDER=0 >-conotoxin PIIIE has beenpurified and characterized from Conuspurpurascens venom. Electrophysiological studies indicatethat the peptide inhibits the nicotinicacetylcholine receptor (nAChR). However, the peptide does notblock the binding of fchars/alpha.gif" BORDER=0>-bungarotoxin, acompetitive nAChR antagonist. Thus, fchars/psi.gif" BORDER=0 >-conotoxinPIIIE appears to inhibit the receptor at a siteotherthan the acetylcholine-binding site. As ascertained by sequenceanalysis, mass spectrometry, and chemicalsynthesis, the peptide has the following covalent structure:HOOCCLYGKCRRYOGCSSASCCQR*(O = 4-trans hydroxyproline; * indicates an amidatedC-terminus). The disulfide connectivity of thetoxin is unrelated to the fchars/alpha.gif" BORDER=0>- or the fchars/alpha.gif" BORDER=0>A-conotoxins, theConus peptide families that are competitiveinhibitorsof the nAChR, but shows homology to the f">-conotoxins (which areNa+ channel blockers).