Structural studies of integral membrane proteins in Salipro stealth carriers

Integral membrane proteins (IMPs) are potential targets for medical applications and are usually extracted with detergent for structural studies. However, SAXS and SANS studies of membrane proteins in detergent micelles are problematic due to the dominating contribution of detergent and empty micelles. Reconstitution of IMPs in Salipro nanoparticles can overcome these obstacles and allow a low-resolution structural analysis of membrane proteins in a detergent free environment. To fully contrast-match out the Salipro nanoparticles, we plan to incorporate our IMP targets in stealth carriers consisting of deuterated Saposin A proteins and lipids and perform a SANS experiment on SANS2D. This would allow a low-resolution structural characterisation of our IMPs of interest in a native-like lipid environment without the often-dominating scattering contribution of the lipid carrier system.

整合膜蛋白 (Integral membrane proteins, IMPs) 是医疗应用的潜在靶点，通常需采用去污剂提取以开展结构研究。然而，在去污剂胶束中开展膜蛋白的小角X射线散射 (Small Angle X-ray Scattering, SAXS) 与小角中子散射 (Small Angle Neutron Scattering, SANS) 研究颇具挑战，究其原因，去污剂与空胶束的散射贡献占据绝对主导地位。将IMPs重构至Salipro纳米颗粒中，可克服上述难题，实现无去污剂环境下膜蛋白的低分辨率结构分析。为了通过衬度匹配完全抵消Salipro纳米颗粒的散射贡献，我们计划将目标IMPs嵌入由氘代萨波辛A (Saposin A) 蛋白与脂质构成的隐形载体中，并在SANS2D仪器上开展SANS实验。此举可实现在类天然脂质环境中对目标IMPs进行低分辨率结构表征，且不会受到脂质载体体系通常占据主导地位的散射干扰。