Primary structure and synthesis of Imperatoxin A (IpTxa), a peptide activator of Ca2+ release channels/ryanodine receptors

FEBS Letters

Possani, Lourival D.¹  Valdivia, Hector H.²  Arévalo, Carolina²  Zamudio, Fernando Z.¹  Walker, Jeffery W.²  Gurrola, Georgina B.²  Sreekumar, Raghava² 

[1] Department of Molecular Recognition and Structural Biology, Biotechnology Institute, National Autonomous University of Mexico, Cuernavaca, Morelos 62271, Mexico;Department of Physiology, University of Wisconsin Medical School, Madison, WI 53706, USA

关键词: Ca2+ release channel;    Sarcoplasmic reticulum;    Pandinus imperator scorpion venom;    Caffeine;    Synthetic peptide;   

DOI  :  10.1016/S0014-5793(97)00227-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We present the complete amino acid sequence of Imperatoxin A (IpTx_a), a 33-amino-acid peptide from the venom of the scorpion P. imperator which activates Ca²⁺ release channels/ryanodine receptors (RyR) of sarcoplasmic reticulum (SR). The amino acid sequence of IpTx_a shows no homology to any scorpion toxin so far described, but shares some homology to the amino acid sequence of Tx2-9 and agelenin, two spider toxins that target neuronal P-type Ca²⁺ channels. We also describe the total synthesis of IpTx_a and demonstrate that it efficiently activates RyRs with potency and affinity identical to those of native IpTx_a. The use of synthetic IpTx_a should help in the identification of the structural motifs of RyR critical for channel gating.

【 授权许可】

Unknown