Low-temperature solid-state 13C NMR studies of the retinal chromophore in rhodopsin.
Low-temperature solid-state 13C NMR studies of the retinal chromophore in rhodopsin.
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视紫红质中视网膜发色团的低温固态 13C NMR 研究。
DOI：
10.1021/bi00380a018
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Griffin,RG
中科院分区：
文献类型：
--
作者：
Smith,SO;Palings,I;Copié,V;Raleigh,DP;Courtin,J;Pardoen,JA;Lugtenburg,J;Mathies,RA;Griffin,RG
弗朗西斯比特国家磁铁实验室和化学系，马萨诸塞州理工学院，剑桥，马萨诸塞州02139，化学系，加州大学，伯克利，加州94720，和化学系，莱顿大学，2300 RA莱顿，荷兰接收于1986年8月12日;修订的手稿接收于1986年11月14日摘要：魔角样品旋转（MASS）的13 C NMR谱已获得的牛视紫红质再生与视网膜的假体基团同位素富含13 C在C-5和C-14。为了观察13 C视网膜发色团共振，必须采用低温（-15--35 ℃）来限制蛋白质的旋转扩散。各向同性的化学位移和主值的化学位移张量的13 C-5标签表明，视网膜生色团是在扭曲的6-S-顺式构象的视紫红质，在细菌视紫红质中发现的平面6-S-反式构象。~（13）C-~（14）各向同性位移和位移张量主值表明Schiff碱C= N键是反键。此外，13 C-14化学位移（121.2ppm）在质子化（C= N反）席夫碱模型化合物所表现出的值（120-123 ppm）的范围内，表明C= N键被质子化。我们的研究结果进行了讨论与视紫红质的波长调节机制。
Francis Bitter National Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands Received August 12, 1986; Revised Manuscript Received November 14, 1986 abstract: Magic angle sample spinning (MASS) 13C NMR spectra have been obtained of bovine rhodopsin regenerated with retinal prosthetic groups isotopically enriched with 13C at C-5 and C-14. In order to observe the 13C retinal chromophore resonances, it was necessary to employ low temperatures (-15—»·-35 C) to restrict rotational diffusion of the protein. The isotropic chemical shift and principal values of the chemical shift tensor of the 13C-5 label indicate that the retinal chromophore is in the twisted 6-s-cis conformation in rhodopsin, in contrast to the planar 6-s-trans conformation found in bacteriorhodopsin. The 13C-14 isotropic shift and shift tensor principal values show that the Schiff base C= N bond is anti. Furthermore, the 13C-14 chemical shift (121.2 ppm) is within the range of values (120-123 ppm) exhibited by protonated (C= N anti) Schiff base model compounds, indicating that the C= N linkage is protonated. Our results are discussed with regard to the mechanism of wavelength regulation in rhodopsin.