Oligomerization of BH4-truncated Bcl-x_L in solution

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• 作者：Youli Wang ; Rong Cao ; Dongxiang Liu ; Adam Chervin ; Jian Yuan ; Jing An ; Ziwei Huang
• 关键词：Bcl-x_L ; Bcl-2 ; BH4 domain ; Truncated Bcl-x_L ; Oligomerization ; Apoptosis
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2007
• 期刊代码：159_0006291x
• 类别：bio
• 出版时间：5 October 2007
• 卷：361
• 期：4
• 页码：1006-1011
• 文件大小：337 K

摘要

BH4 domain is critical for the anti-apoptotic functions of Bcl-2 and Bcl-x_L and their binding abilities with other members of the Bcl-2 family. The cleavage of the BH4 domain in Bcl-x_L and Bcl-2 by caspase 1 or 3 converts the anti-apoptotic Bcl-x_L and Bcl-2 into pro-apoptotic proteins that potently induce apoptosis. Herein, we report that recombinant Bcl-x_L proteins without N-terminal 61 residues, His₆-NΔ61-Bcl-x_L-CΔ21 and NΔ61-Bcl-x_L-CΔ21, form oligomers in solution, whereas Bcl-x_L-CΔ21 exists as a monomer. The oligomerization of the truncated proteins is independent of protein–lipid interaction, protein concentration or the ion strength of the solution. Circular dichroism spectrum shows a significant decrease in the content of α-helices upon deletion of N-terminal residues. NΔ61-Bcl-x_L-CΔ21 also loses its heterodimerization capability with the BH3 peptide derived from Bak. This newly acquired property might be linked to its ability to induce apoptosis in cells.