Scalettar B A, Abney J R, Owicki J C
Chemical Biodynamics Division, Lawrence Berkeley Laboratory, CA 94720.
Proc Natl Acad Sci U S A. 1988 Sep;85(18):6726-30. doi: 10.1073/pnas.85.18.6726.
Self diffusion and mutual diffusion in two-dimensional membrane systems are analyzed. It is shown that interprotein interactions can produce markedly different density-dependent changes in the diffusion coefficients describing these two processes; the qualitative differences are illustrated by using a theoretical formalism valid for dilute solutions. Results are obtained for three analytical potentials: hard-core repulsions, soft repulsions, and soft repulsions with weak attractions. Self diffusion is inhibited by all three interactions. In contrast, mutual diffusion is inhibited by attractions but is enhanced by repulsions. It is shown that such interaction-dependent differences in self diffusion and mutual diffusion could underlie, among other things, the disparity in protein diffusion coefficients extracted from fluorescence recovery after photobleaching and postelectrophoresis relaxation data.
分析了二维膜系统中的自扩散和互扩散。结果表明，蛋白质间相互作用可在描述这两个过程的扩散系数中产生明显不同的密度依赖性变化；利用适用于稀溶液的理论形式对定性差异进行了说明。针对三种解析势得到了结果：硬核排斥、软排斥以及带有弱吸引作用的软排斥。所有这三种相互作用均抑制自扩散。相比之下，互扩散受到吸引作用的抑制，但受到排斥作用的增强。结果表明，自扩散和互扩散中这种依赖于相互作用的差异可能是除其他因素外，从光漂白后荧光恢复和电泳后弛豫数据中提取的蛋白质扩散系数存在差异的原因。
