Scalettar B A, Abney J R, Hackenbrock C R
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599-7090.
Proc Natl Acad Sci U S A. 1991 Sep 15;88(18):8057-61. doi: 10.1073/pnas.88.18.8057.
The coupling between molecular diffusion and the structure and function of the rat liver mitochondrial matrix was explored using fluorescence anisotropy techniques and electron microscopy. The results confirm that matrix ultrastructure and the concentration of matrix protein are influenced by the respiratory state of mitochondria and the osmolarity of the external medium. At physiological osmolarity, a fluorescent metabolite-sized probe was found to diffuse slowly in the mitochondrial matrix but not to be completely immobile. In addition, significant differences in diffusion rates were found to exist between different mitochondrial respiratory states, with the slowest diffusion occurring in states with the highest matrix protein concentration. These data support the concept of a matrix structure in which diffusion is considerably hindered due to limited probe-accessible water and further suggest that volume-dependent regulation of matrix protein packing may modulate metabolite diffusion and, in turn, mitochondrial metabolism.
利用荧光各向异性技术和电子显微镜研究了大鼠肝脏线粒体基质中分子扩散与结构和功能之间的耦合关系。结果证实，基质超微结构和基质蛋白浓度受线粒体呼吸状态和外部介质渗透压的影响。在生理渗透压下，发现一种荧光代谢物大小的探针在线粒体基质中扩散缓慢，但并非完全不移动。此外，发现不同线粒体呼吸状态之间存在显著的扩散速率差异，在基质蛋白浓度最高的状态下扩散最慢。这些数据支持了一种基质结构的概念，即由于探针可及水有限，扩散受到显著阻碍，并进一步表明基质蛋白堆积的体积依赖性调节可能会调节代谢物扩散，进而调节线粒体代谢。
