Tertiary interactions between the fifth and sixth transmembrane segments of rhodopsin.
Tertiary interactions between the fifth and sixth transmembrane segments of rhodopsin.
复制标题
视紫红质第五和第六跨膜片段之间的三级相互作用。
DOI：
10.1021/bi9902384
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发表时间：
1999
期刊：
影响因子：
2.9
通讯作者：
Oprian,DD
中科院分区：
文献类型：
--
作者：
Struthers,M;Yu,H;Kono,M;Oprian,DD
我们在分裂视紫红质构建体中使用半胱氨酸扫描诱变和二硫键交联来研究视紫红质第五（TM5）和第六（TM6）跨膜片段的二级结构和三级接触。通过简单增加 pH 值来促进二硫键形成，TM5（位置 198、200 和 204）和 TM6（位置 276）胞外侧残基之间的三个交联已被识别和表征。观察到的交联螺旋模式表明第五跨膜螺旋延伸穿过残基 200，但不包括残基 198。含有这些二硫化物的视紫红质突变体表现出类似天然的吸收光谱和转导蛋白的光依赖性激活，表明 TM5 相对于 TM6 的胞外侧的大运动对于受体激活来说不是必需的。
We have used cysteine scanning mutagenesis and disulfide cross-linking in a split rhodopsin construct to investigate the secondary structure and tertiary contacts of the fifth (TM5) and sixth (TM6) transmembrane segments of rhodopsin. Using a simple increase in pH to promote disulfide bond formation, three cross-links between residues on the extracellular side of TM5 (at positions 198, 200, and 204) and TM6 (at position 276) have been identified and characterized. The helical pattern of cross-linking observed indicates that the fifth transmembrane helix extends through residue 200 but does not include residue 198. Rhodopsin mutants containing these disulfides demonstrate nativelike absorption spectra and light-dependent activation of transducin, suggesting that large movements on the extracellular side of TM5 with respect to TM6 are not required for receptor activation.