Faculty of Biology, St. Kl. Ohridski University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
Biochem Biophys Res Commun. 2012 Mar 23;419(4):648-51. doi: 10.1016/j.bbrc.2012.02.067. Epub 2012 Feb 20.
The interaction of monogalactosyldiacylglycerol (MGDG) with cytochrome b(6)f complex (cyt b(6)f), a major component of the photosynthetic apparatus, was studied in Langmuir monolayers during compression/expansion cycling and at constant surface pressure mode. The surface pressure/area isotherms of the mixed films were analyzed in terms of surface compressional modulus and two-dimensional virial equation of state. The morphology and the surface potential of the monolayers were monitored by Brewster angle microscopy and vibrating plate sensor respectively. Our results suggested that there is a specific interaction between MGDG and cyt b(6)f which resulted in depletion of lipid molecules from the interface. The current work sheds light on the still unclear question how b(6)f complex gets in touch with the major compound of the thylakoid membranes, the non-charged lipid MGDG. The interaction occured even at very low sub-nanomolar concentration of the complex. This effect most probably could be attributed to hydrogen bonding between the galactose headgroup of the lipid and the protein moiety of cyt b(6)f.
在 Langmuir 单分子层中，通过压缩/扩张循环和恒表面压模式，研究了单半乳糖二酰基甘油（MGDG）与细胞色素 b6f 复合物（cyt b6f）之间的相互作用。用表面压缩模量和二维 Virial 状态方程对混合膜的表面压力/面积等温线进行了分析。通过布鲁斯特角显微镜和振动板传感器分别监测了单分子层的形态和表面电势。我们的结果表明，MGDG 和 cyt b6f 之间存在特定的相互作用，导致脂质分子从界面耗尽。目前的工作阐明了一个仍不清楚的问题，即 b6f 复合物如何与类囊体膜的主要化合物、不带电荷的脂质 MGDG 接触。即使在复合物的亚纳摩尔浓度非常低的情况下，这种相互作用也会发生。这种效应很可能归因于脂质的半乳糖头部基团与 cyt b6f 的蛋白质部分之间的氢键。
