Red-shifting mutation of light-driven sodium-pump rhodopsin
Red-shifting mutation of light-driven sodium-pump rhodopsin
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DOI：
10.1038/s41467-019-10000-x
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发表时间：
2019-04-30
影响因子：
16.6
通讯作者：
Kandori, Hideki
中科院分区：
文献类型：
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作者：
Inoue, Keiichi;Marin, Maria del Carmen;Kandori, Hideki
微生物视紫红质是利用光能运输各种离子的光感受膜蛋白。虽然它们被广泛用于光遗传学以光学控制神经元活动，但由于它们的低光毒性和高组织渗透性，对具有较长波长光功能的视紫红质的需求很高。在这里，我们通过改变视网膜发色团（KR 2 P219 T/S254 A）周围残基的偶极矩，实现了钠泵视紫红质（KR 2）吸收波长的40 nm红移，而不损害其离子转运活性。通过傅里叶变换红外光谱法观察到红移蛋白质的发色团与野生型的发色团的结构差异。QM/MM模型生成的自动化协议表明，蛋白质和生色团之间的静电相互作用的氨基酸取代引起的变化，降低了地面和第一电子激发态之间的能隙。基于这些见解，一个天然的钠泵与红移的吸收是确定从Jannaschia seosinensis。
Microbial rhodopsins are photoreceptive membrane proteins that transport various ions using light energy. While they are widely used in optogenetics to optically control neuronal activity, rhodopsins that function with longer-wavelength light are highly demanded because of their low phototoxicity and high tissue penetration. Here, we achieve a 40-nm red-shift in the absorption wavelength of a sodium-pump rhodopsin (KR2) by altering dipole moment of residues around the retinal chromophore (KR2 P219T/S254A) without impairing its iontransport activity. Structural differences in the chromophore of the red-shifted protein from that of the wildtype are observed by Fourier transform infrared spectroscopy. QM/MM models generated with an automated protocol show that the changes in the electrostatic interaction between protein and chromophore induced by the amino-acid replacements, lowered the energy gap between the ground and the first electronically excited state. Based on these insights, a natural sodium pump with red-shifted absorption is identified from Jannaschia seosinensis.