单独的极性残留物对膜蛋白稳定性和结构的影响
Yu-Chu Chang1, Zheng Cao2, Wai-Ting Chen3
1Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; International Ph.D. Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Biochimica et biophysica acta. Biomembranes
|April 23, 2024
概括
膜蛋白可以在它们的跨膜螺旋体内结合极性残留物. 将极性阿斯巴拉金残留物引入巴克蒂埃罗多普辛,降低了稳定性,但形成了稳定键,对这种突变表现出耐受性.
科学领域:
- 结构生物学是结构生物学.
- 膜蛋白生物物理学 膜蛋白生物物理学
- 蛋白质工程是一种蛋白质工程.
背景情况:
- 膜蛋白中的跨膜螺旋 (TM) 通常是疏水的,由非极性残留物组成.
- 在TM领域的极性残留物往往是功能性的,参与结构相互作用,寡合化或催化.
- 在TM螺旋中能量不利的,独立的极性残留物对能量成本和结构后果的了解很少.
研究的目的:
- 研究将极性残留物引入到膜蛋白的疏水性TM域中的稳定性和结构影响.
- 用bacteriorhodopsin (bR) 作为一个模型系统,系统地研究无极到极地突变的影响.
主要方法:
- 在17个无极Leu或Phe残留物的系统性位点导向突变发生到bacteriorhodopsin中的极Asn.
- 使用生物物理测量量对突变bR稳定性的量化.
- 分析影响不稳定的结构因素,包括可访问的表面积和膜深度.
- 引入的Asn残留物的结构研究,以了解它们的相互作用.
主要成果:
- 在bR的TM域中的所有极置换 (Leu/Phe到Asn) 都导致蛋白质稳定性降低.
- 稳定性减少的程度与结构因素相关,例如突变部位的相对可访问的表面积和膜深度.
- 结构分析显示,引入的Asn残留物形成了侧链到脊柱的键,减轻了疏水环境中不利的能量.
结论:
- 膜蛋白可以在它们的TM区域内容纳单个极性残留物,而不会完全破坏结构.
- 稳定键形成是减轻水TM环境中非原生极性残留物能量惩罚的关键机制.
- 这项研究提供了关于膜蛋白结构对极性残留物结合的耐受性和适应性的见解.
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