Shubin V V, Roegner M, El-Mohsnawy E, Terekhova I V, Schlodder E, Karapetian N V
Prikl Biokhim Mikrobiol. 2010 May-Jun;46(3):299-307.
Circular dichroism (CD) spectra of photosystem I (PSI) complexes of the cyanobacteria Thermosynechococcus elongatus, Arthrospira platensis and Synechocystis sp. PCC 6803 were studied. CD spectra of dark-adapted PSI trimers and monomers, measured at 77 K, show common bands at 669-670(+), 673(+), 680(-), 683-685(-), 696-697(-), 702(-) and 711(-) nm. The intensities of these bands are species specific. In addition, bands at 683-685(-) and 673(+) nm differ in intensity for trimeric and monomeric PSI complexes. CD difference spectra (P700(+)-P700) of PSI complexes at 283 K exhibit conservative bands at 701(-) and 691(+) nm due to changes in resonance interaction of chlorophylls in the reaction center upon oxidation of P700. Additional bands are observed at 671(-), 678(+), 685(-), 693(-) nm and in the region 720-725 nm those intensities correlate with intensities of analogous bands of antenna chlorophylls in dark-adapted CD spectra. It is suggested that the variability of CD difference spectra of PSI complexes is determined by changes in resonance interaction of reaction center chlorophylls with closely located antenna chlorophylls.
对嗜热栖热放线菌、钝顶节旋藻和聚球藻属PCC 6803的光系统I（PSI）复合物的圆二色性（CD）光谱进行了研究。在77 K下测量的暗适应PSI三聚体和单体的CD光谱在669 - 670（+）、673（+）、680（-）、683 - 685（-）、696 - 697（-）、702（-）和711（-）nm处显示出共同的谱带。这些谱带的强度具有物种特异性。此外，683 - 685（-）和673（+）nm处的谱带在三聚体和单体PSI复合物中的强度不同。在283 K下PSI复合物的CD差光谱（P700（+） - P700）由于P700氧化时反应中心叶绿素共振相互作用的变化，在701（-）和691（+）nm处呈现保守谱带。在671（-）、678（+）、685（-）、693（-）nm以及720 - 725 nm区域观察到额外的谱带，其强度与暗适应CD光谱中天线叶绿素类似谱带的强度相关。有人认为，PSI复合物CD差光谱的变化性是由反应中心叶绿素与紧密相邻的天线叶绿素共振相互作用的变化所决定的。
