Diffusion properties of single FoF1-ATP synthases in a living bacterium unraveled by localization microscopy
Diffusion properties of single FoF1-ATP synthases in a living bacterium unraveled by localization microscopy
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定位显微镜揭示活细菌中单个 FoF1-ATP 合酶的扩散特性
DOI：
10.1117/12.907089
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发表时间：
2012
影响因子：
11.1
通讯作者：
M. Börsch
中科院分区：
文献类型：
--
作者：
Marc Renz;T. Rendler;M. Börsch
大肠杆菌中的FoF1-ATP合成酶是一种膜结合酶，它利用内部质子驱动的旋转双马达催化合成三磷酸腺苷(ATP)。根据“化学渗透假说”，一系列质子泵在细菌质膜上产生必要的pH差和电势。这些质子泵是氧化还原偶联的膜酶，可能以超复合体的形式组织，如线粒体内膜中的相关酶所示。我们报道了通过定位显微镜和单酶跟踪在活体大肠杆菌中对单一荧光FoF1-ATP合酶进行扩散测量，以区分细菌膜中的单体酶和超复杂结合形式。对于定量的均方位移(MSD)分析，必须考虑具有显著膜曲率的膜中观察区域的有限大小。由于表面坐标系的定位精度不同，我们采用滑动观察窗的方法得到了FoF1-μ合酶在活体细胞中的扩散系数D=0.072μm2/S。
FoF1-ATP synthases in Escherichia coli (E. coli) bacteria are membrane-bound enzymes which use an internal protondriven rotary double motor to catalyze the synthesis of adenosine triphosphate (ATP). According to the 'chemiosmotic hypothesis', a series of proton pumps generate the necessary pH difference plus an electric potential across the bacterial plasma membrane. These proton pumps are redox-coupled membrane enzymes which are possibly organized in supercomplexes, as shown for the related enzymes in the mitochondrial inner membrane. We report diffusion measurements of single fluorescent FoF1-ATP synthases in living E. coli by localization microscopy and single enzyme tracking to distinguish a monomeric enzyme from a supercomplex-associated form in the bacterial membrane. For quantitative mean square displacement (MSD) analysis, the limited size of the observation area in the membrane with a significant membrane curvature had to be considered. The E. coli cells had a diameter of about 500 nm and a length of about 2 to 3 μm. Because the surface coordinate system yielded different localization precision, we applied a sliding observation window approach to obtain the diffusion coefficient D = 0.072 μm2/s of FoF1-ATP synthase in living E. coli cells.
DOI：
10.1073/pnas.1103621108
发表时间：
2011-08-23
影响因子：
11.1
作者：
Davies, Karen M.;Strauss, Mike;Kuehlbrandt, Werner
通讯作者：
Kuehlbrandt, Werner