Structural Foundations of Potassium Selectivity in Channelrhodopsins.
Structural Foundations of Potassium Selectivity in Channelrhodopsins.
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钾离子选择性通道视紫红质（KCRs）是最近在链藻类原生物Hyphochytriumcatenoides中发现的光门控钾离子通道。当在神经元中表达时，KCR能够高精度地抑制尖峰（光遗传学沉默）。KCR能够区分K+和Na+，而无需经典K+通道中发现的传统K+选择性过滤器。H. catenoides还编码对Na+比对K+更易渗透的第三种parabolic。为了确定KCRs的K+选择性异常负责的结构基序，我们系统地分析了一系列的嵌合体和突变体的这种蛋白质。我们发现，三个关键的残基的突变，在paralcohol转换其Na+-选择性通道到K+-选择性之一。我们对来自其他原生生物（Colponema vietnamica，Cafeteria burkhardae和Chromera velia）和宏基因组样品的同源蛋白质的表征证实了这些残基对K+选择性的重要性。我们还发现Trp 102和Asp 116在所有三个H. catenoides旁系同源物，是必要的，虽然不是足够的，K+的选择性。我们的研究结果为进一步工程化KCR以满足光遗传学需求提供了基础。
Potassium-selective channelrhodopsins (KCRs) are light-gated K+ channels recently found in the stramenopile protist Hyphochytrium catenoides. When expressed in neurons, KCRs enable high-precision optical inhibition of spiking (optogenetic silencing). KCRs are capable of discriminating K+ from Na+ without the conventional K+ selectivity filter found in classical K+ channels. The genome of H. catenoides also encodes a third paralog that is more permeable for Na+ than for K+. To identify structural motifs responsible for the unusual K+ selectivity of KCRs, we systematically analyzed a series of chimeras and mutants of this protein. We found that mutations of three critical residues in the paralog convert its Na+-selective channel into a K+-selective one. Our characterization of homologous proteins from other protists (Colponema vietnamica, Cafeteria burkhardae, and Chromera velia) and metagenomic samples confirmed the importance of these residues for K+ selectivity. We also show that Trp102 and Asp116, conserved in all three H. catenoides paralogs, are necessary, although not sufficient, for K+ selectivity. Our results provide the foundation for further engineering of KCRs for optogenetic needs.
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影响因子：
64.5
作者：
Kishi KE;Kim YS;Fukuda M;Inoue M;Kusakizako T;Wang PY;Ramakrishnan C;Byrne EFX;Thadhani E;Paggi JM;Matsui TE;Yamashita K;Nagata T;Konno M;Quirin S;Lo M;Benster T;Uemura T;Liu K;Shibata M;Nomura N;Iwata S;Nureki O;Dror RO;Inoue K;Deisseroth K;Kato HE
通讯作者：
Kato HE
影响因子：
16.6
作者：
Govorunova EG;Sineshchekov OA;Li H;Spudich JL
通讯作者：
Spudich JL
影响因子：
14.9
作者：
Chen, I-Min A.;Chu, Ken;Kyrpides, Nikos C.
通讯作者：
Kyrpides, Nikos C.
影响因子：
25
作者：
Boyden, ES;Zhang, F;Deisseroth, K
通讯作者：
Deisseroth, K
影响因子：
2.9
作者：
BROWN, LS;GAT, Y;LANYI, JK
通讯作者：
LANYI, JK