ATTACHMENT SITE(S) OF RETINAL IN BACTERIORHODOPSIN
ATTACHMENT SITE(S) OF RETINAL IN BACTERIORHODOPSIN
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DOI：
10.1073/pnas.78.7.4068
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发表时间：
1981-01-01
期刊：
影响因子：
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通讯作者：
STROUD, RM
中科院分区：
文献类型：
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作者：
KATRE, NV;WOLBER, PK;STROUD, RM
在盐生盐杆菌菌视紫红质中的视黄基-赖氨酸席夫碱键的化学还原之后，视黄基残基共价连接到Lys-216（在Lys-172上可能具有小部分）或连接到Lys-216（172）和Lys-40/41两者。连接位点（在Lys-216上高达100%;在Lys-40/41上高达70%）取决于温度、样品在光照或黑暗中是否还原以及样品是否适应光照或黑暗。吸光度和圆二色性光谱表明，视黄基残基在光照下还原后仍处于其原始结合位点。因此，不同的附着位点可以反映在光反应周期期间或在光/暗适应期间发生的变化，或在细菌视紫红质的结构中与赖氨酸接近的正常连接的偶然的生理上不相关的席夫碱连接的减少。在任何一种情况下，视网膜都不会离开其结合位点。这最后一点严重限制了细菌视紫红质三级结构中氨基酸序列的可能排列，并清楚地区分了与所有标准一致的2种模型。
After chemical reduction of the retinylidene-lysine Schiff base linkage in Halobacterium halobium bacteriorhodopsin, the retinyl residue is covalently attached to Lys-216 (with a possible minor fraction on Lys-172) or to both Lys-216(172) and Lys-40/41. The linkage site (up to 100% on Lys-216; up to 70% on Lys-40/41) depends on temperature, whether the sample is reduced in the light or dark and whether the sample is light or dark adapted. Absorbance and circular dichroism spectra indicate that the retinyl residue is in its original binding site after reduction in the light. Thus, the different attachment sites may reflect changes that occur during the photoreaction cycle or during light/dark adaptation, or the reduction of accidental physiologically irrelevant Schiff base linkages to lysines close to the normal linkage in the structure of bacteriorhodopsin. In either case, the retinal does not leave its binding site. This last point severely limits the possible arrangements of the amino acid sequence in the bacteriorhodopsin tertiary structure and clearly distinguishes 2 models that are consistent with all criteria.