Light-induced global conformational change of photoactive yellow protein in solution
Light-induced global conformational change of photoactive yellow protein in solution
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DOI：
10.1021/bi0264768
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发表时间：
2002-11-19
期刊：
影响因子：
2.9
通讯作者：
Kataoka, M
中科院分区：
文献类型：
--
作者：
Imamoto, Y;Kamikubo, H;Kataoka, M
利用小角X射线散射（SAXS）技术直接观察了光敏黄蛋白光诱导的全局构象变化。N-末端6、15或23个氨基酸残基被酶促截短（分别为T6、T15或T23），并且它们的近UV中间体在连续照明下积累用于SAXS测量。Kratky图表明，照明引起的部分损失的球形。在T6中球形度的变化是显著的，但在T15和T23中非常小，这表明在位置7-15中的结构变化主要降低球形度。通过Guinier图估计的回转半径（R-g）在光照下对于T6增加了1.1埃，对于T15和T23增加了0.7埃。由于T23缺乏大部分N-末端环，由PAS核心、螺旋连接体和P-支架组成的主要部分的结构变化导致R-g增加0.7埃。位置7-15的结构变化导致额外增加0.4埃。对于暗态，在截断位置7-15时R-g的减小为0.3埃，而对于中间体的R-g的减小为0.7埃，这表明该区域在中间体形成时向外移动。这些结果表明，光诱导PYP的结构变化发生在主要部分和N-末端15个氨基酸残基。前者仅引起尺寸的增加，而后者导致形状的额外变化。
The light-induced global conformational change of photoactive yellow protein was directly observed by small-angle X-ray scattering (SAXS). The N-terminal 6, 15, or 23 amino acid residues were enzymatically truncated (T6, T15, or T23, respectively), and their near-UV intermediates were accumulated under continuous illumination for SAXS measurements. The Kratky plot demonstrated that illumination induced partial loss of globularity. The change in globularity was marked in T6 but very small in T 15 and T23, suggesting that structural change in positions 7-15 mainly reduces the globularity. The radius of gyration (R-g) estimated by Guinier plot was increased by 1.1 Angstrom for T6 and 0.7 Angstrom for T15 and T23 upon illumination. As T23 lacks most of the N-terminal loop, structural change in the main part composed of the PAS core, helical connector, and P-scaffold caused an increase of R-g by 0.7 Angstrom. The structural change of positions 7-15 caused an additional increase by 0.4 Angstrom. The decrease of R-g upon truncation of positions 7-15 for dark state was 0.3 Angstrom, while that for the intermediate was 0.7 Angstrom, suggesting that this region moves outward on formation of the intermediate. These results indicate that a light-induced structural change of PYP takes place in the main part and N-terminal 15 amino acid residues. The former induces only dimensional increase, but the latter results in additional change in shape.