Probing origins of molecular interactions stabilizing the membrane proteins halorhodopsin and bacteriorhodopsin
Probing origins of molecular interactions stabilizing the membrane proteins halorhodopsin and bacteriorhodopsin
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DOI：
10.1016/j.str.2004.12.005
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发表时间：
2005-02-01
期刊：
影响因子：
5.7
通讯作者：
Müller, DJ
中科院分区：
文献类型：
--
作者：
Cisneros, DA;Oesterhelt, D;Müller, DJ
采用单分子原子力显微镜和光谱学技术，研究了盐酸盐细菌光驱动氯泵halorhodopsin （HR）稳定结构的分子相互作用。由于HR和细菌视紫红质之间的结构和序列高度相似，我们比较了它们的展开途径和建立结构稳定片段的多肽区域。展开途径和稳定蛋白质的结构片段都表现出非常高的相似性。这表明不同的氨基酸组成可以建立结构上难以区分的能垒。这些稳定结构域是由结构区域内所有氨基酸的综合相互作用产生的，而不是由特定相互作用产生的。然而，在螺旋E的短段内检测到一个额外的展开屏障。该屏障与Pi-bulk相互作用相关，该相互作用局部破坏螺旋E并分裂结构稳定段。
Single-molecule atomic force microscopy and spectroscopy were applied to detect molecular interactions stabilizing the structure of halorhodopsin (HR), a light-driven chloride pump from Halobacterium salinarum. Because of the high structural and sequence similarities between HR and bacteriorhodopsin, we compared their unfolding pathways and polypeptide regions that established structurally stable segments against unfolding. Unfolding pathways and structural segments stabilizing the proteins both exhibited a remarkably high similarity. This suggests that different amino acid compositions can establish structurally indistinguishable energetic barriers. These stabilizing domains rather result from comprehensive interactions of all amino acids within a structural region than from specific interactions. However, one additional unfolding barrier located within a short segment of helix E was detected for HR. This barrier correlated with a Pi-bulk interaction, which locally disrupts helix E and divides a structural stabilizing segment.