通过诱变和X射线晶体学揭示的放氧光系统II中PsbY的定位
Location of PsbY in oxygen-evolving photosystem II revealed by mutagenesis and X-ray crystallography.
作者信息
Kawakami Keisuke, Iwai Masako, Ikeuchi Masahiko, Kamiya Nobuo, Shen Jian-Ren
机构信息
Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University, Okayama 700-8530, Japan.
出版信息
FEBS Lett. 2007 Oct 16;581(25):4983-7. doi: 10.1016/j.febslet.2007.09.036. Epub 2007 Sep 29.
PsbY is one of the low molecular mass subunits of oxygen-evolving photosystem II (PSII). Its location, however, has not been identified in the current crystal structure of PSII. We constructed a PsbY-deletion mutant of Thermosynechococcus elongatus, crystallized, and analyzed the crystal structure of the mutant PSII dimer. The results obtained showed that PsbY is located in the periphery of PSII close to the alpha- and beta-subunits of cytochrome b559, which corresponded to an unassigned helix in the 3.7A structure of T. vulcanus or helix X2 in the 3.0A structure of T. elongatus. Our results also indicated that the C-terminal loop of PsbY is protruded toward the stromal side, instead of the lumenal side predicted previously.
PsbY是放氧光系统II（PSII）的低分子量亚基之一。然而，其在目前PSII晶体结构中的位置尚未确定。我们构建了嗜热栖热放线菌的PsbY缺失突变体，进行结晶，并分析了突变体PSII二聚体的晶体结构。所得结果表明，PsbY位于PSII的外周，靠近细胞色素b559的α亚基和β亚基，这与火山栖热放线菌3.7埃结构中一个未确定的螺旋或嗜热栖热放线菌3.0埃结构中的螺旋X2相对应。我们的结果还表明，PsbY的C末端环向基质侧突出，而不是先前预测的腔侧。
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