3PLC

Crystal structure of Beta-Cardiotoxin, a novel three-finger cardiotoxin from the venom of Ophiophagus hannah

3PLC の概要

• エントリーDOI: 10.2210/pdb3plc/pdb
• 分子名称: Beta-cardiotoxin OH-27 (1 entity in total)
• 機能のキーワード: beta-cardiotoxin, beta-sheet, novel cardiotoxin, toxin
• 由来する生物種: Ophiophagus hannah (King cobra)
• 細胞内の位置: Secreted : Q69CK0
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 21094.39

構造登録者

Roy, A.,Qingxiang, S.,Kini, R.M.,Sivaraman, J. (登録日: 2010-11-15, 公開日: 2011-11-16, 最終更新日: 2024-11-13)

主引用文献

Roy, A.,Qingxiang, S.,Alex, C.,Rajagopalan, N.,Jobichen, C.,Sivaraman, J.,Kini, R.M.
Identification of a alpha-helical molten globule intermediate and structural characterization of beta-cardiotoxin, an all beta-sheet protein isolated from the venom of Ophiophagus hannah (king cobra).
Protein Sci., 28:952-963, 2019

PubMed Abstract: β-Cardiotoxin is a novel member of the snake venom three-finger toxin (3FTX) family. This is the first exogenous protein to antagonize β-adrenergic receptors and thereby causing reduction in heart rates (bradycardia) when administered into animals, unlike the conventional cardiotoxins as reported earlier. 3FTXs are stable all β-sheet peptides with 60-80 amino acid residues. Here, we describe the three-dimensional crystal structure of β-cardiotoxin together with the identification of a molten globule intermediate in the unfolding pathway of this protein. In spite of the overall structural similarity of this protein with conventional cardiotoxins, there are notable differences observed at the loop region and in the charge distribution on the surface, which are known to be critical for cytolytic activity of cardiotoxins. The molten globule intermediate state present in the thermal unfolding pathway of β-cardiotoxin was however not observed during the chemical denaturation of the protein. Interestingly, circular dichroism (CD) and NMR studies revealed the presence of α-helical secondary structure in the molten globule intermediate. These results point to substantial conformational plasticity of β-cardiotoxin, which might aid the protein in responding to the sometimes conflicting demands of structure, stability, and function during its biological lifetime.

PubMed: 30891862
DOI: 10.1002/pro.3605

実験手法

X-RAY DIFFRACTION (2.41 Å)