Solution structure of γ-bungarotoxin: The functional significance of amino acid residues flanking the RGD motif in integrin binding

Jia Hau Shiu, Chiu Yueh Chen, Long Sen Chang, Yi Chun Chen, Yen Chin Chen, Yu Hui Lo, Yu Chen Liu, Woei Jer Chuang

研究成果: Article同行評審

28 引文 斯高帕斯(Scopus)

摘要

γ-Bungarotoxin, a snake venom protein isolated from Bungarus multicinctus, contains 68 amino acids, including 10 cysteine residues and a TAVRGDGP sequence at positions 30-37. The solution structure of γ-bungarotoxin has been determined by nuclear magnetic resonance (NMR) spectroscopy. The structure is similar to that of the short-chain neurotoxins that contain three loops extending from a disulfide-bridged core. The tripeptide Arg-Gly-Asp (RGD) sequence is located at the apex of the flexible loop and is similar to that of other RGD-containing proteins. However, γ-bungarotoxin only inhibits platelet aggregations with an IC50 of 34 μM. To understand its weak activity in inhibiting platelet aggregation, we mutated the RGD loop sequences of rhodostomin, a potent platelet aggregation inhibitor, from RIPRGDMP to TAVRG-DGP, resulting in a 196-fold decrease in activity. In addition, the average Cα-to-Cα distance between R33 and G36 of γ-bungarotoxin is 6.02 Å, i.e., shorter than that of other RGD-containing proteins that range from 6.55 to 7.46 Å. These results suggested that the amino acid residues flanking the RGD motif might control the width of the RGD loop. This structural difference may be responsible for its decrease in platelet aggregation inhibition compared with other RGD-containing proteins.

原文English
頁(從 - 到)839-849
頁數11
期刊Proteins: Structure, Function and Genetics
57
發行號4
DOIs
出版狀態Published - 2004 十二月 1

All Science Journal Classification (ASJC) codes

  • 結構生物學
  • 生物化學
  • 分子生物學

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