Noguchi T, Inoue Y
Photosynthesis Research laboratory, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
FEBS Lett. 1995 Aug 21;370(3):241-4. doi: 10.1016/0014-5793(95)00833-u.
A Fourier transform infrared (FTIR) difference spectrum upon photooxidation of the accessory chlorophyll (Chlz) of photosystem II (PS II) was obtained at 210 K with Mn-depleted PS II membranes in the presence of fericyanide and silicomolybdate. The observed Chlz+/Chlz spectrum showed two differential bands at 1747/1736 and 1714/1684 cm-1. The former was assigned to the free carbomethoxy C = 0 and the latter to the keto C = 0 that is hydrogen-bonded or in a highly polar environment. Also, the negative 1614 cm-1 band assignable to the macrocycle mode indicated 5-coordination of the central Mg. The negative 1660 cm-1 band, possibly due to the strongly hydrogen-bonded keto C = 0, may suggest oxidation of one more Chlz, although an alternative assignment, the amide I mode of proteins perturbed by Chlz oxidation, is also possible.
在210 K下，利用缺锰的光系统II（PS II）膜，在铁氰化物和硅钼酸盐存在的情况下，获得了光系统II（PS II）辅助叶绿素（Chlz）光氧化后的傅里叶变换红外（FTIR）差谱。观察到的Chlz+/Chlz光谱在1747/1736和1714/1684 cm-1处有两个差分带。前者归属于游离的甲氧羰基C = O，后者归属于氢键结合或处于高极性环境中的酮基C = O。此外，可归因于大环模式的1614 cm-1负带表明中心镁为五配位。1660 cm-1负带可能是由于强氢键结合的酮基C = O，这可能表明又有一个Chlz被氧化，尽管另一种归属，即受Chlz氧化扰动的蛋白质的酰胺I模式也是可能的。
