van de Meene Allison M L, Sharp William P, McDaniel Jennifer H, Friedrich Heiner, Vermaas Wim F J, Roberson Robert W
School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
Biochim Biophys Acta. 2012 May;1818(5):1427-34. doi: 10.1016/j.bbamem.2012.01.019. Epub 2012 Jan 27.
Cells of Synechocystis sp. PCC 6803 lacking photosystem I (PSI-less) and containing only photosystem II (PSII) or lacking both photosystems I and II (PSI/PSII-less) were compared to wild type (WT) cells to investigate the role of the photosystems in the architecture, structure, and number of thylakoid membranes. All cells were grown at 0.5μmol photons m(-2)s(-1). The lumen of the thylakoid membranes of the WT cells grown at this low light intensity were inflated compared to cells grown at higher light intensity. Tubular as well as sheet-like thylakoid membranes were found in the PSI-less strain at all stages of development with organized regular arrays of phycobilisomes on the surface of the thylakoid membranes. Tubular structures were also found in the PSI/PSII-less strain, but these were smaller in diameter to those found in the PSI-less strain with what appeared to be a different internal structure and were less common. There were fewer and smaller thylakoid membrane sheets in the double mutant and the phycobilisomes were found on the surface in more disordered arrays. These differences in thylakoid membrane structure most likely reflect the altered composition of photosynthetic particles and distribution of other integral membrane proteins and their interaction with the lipid bilayer. These results suggest an important role for the presence of PSII in the formation of the highly ordered tubular structures.
将集胞藻6803株系中缺乏光系统I（无光系统I）且仅含有光系统II（PSII）的细胞，或同时缺乏光系统I和II（无光系统I/II）的细胞与野生型（WT）细胞进行比较，以研究光系统在类囊体膜的结构、构造和数量方面的作用。所有细胞均在0.5μmol光子·m⁻²·s⁻¹的光照条件下培养。与在较高光照强度下培养的细胞相比，在此低光照强度下培养的WT细胞的类囊体膜腔膨胀。在无光系统I的菌株发育的各个阶段均发现了管状以及片状的类囊体膜，类囊体膜表面有排列规则的藻胆体。在无光系统I/II的菌株中也发现了管状结构，但这些结构的直径比无光系统I的菌株中的小，其内部结构似乎不同，且不太常见。双突变体中的类囊体膜片较少且较小，藻胆体在表面上的排列更无序。类囊体膜结构的这些差异很可能反映了光合颗粒组成的改变、其他整合膜蛋白的分布及其与脂质双层的相互作用。这些结果表明PSII的存在在高度有序的管状结构形成中起重要作用。
