Department of Living Matter Physics, Max Planck Institute for Dynamics and Self-Organization, D-37077 Göttingen, Germany.
Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3PU, United Kingdom.
Proc Natl Acad Sci U S A. 2020 Jun 2;117(22):11894-11900. doi: 10.1073/pnas.1919635117. Epub 2020 May 15.
Many functional units in biology, such as enzymes or molecular motors, are composed of several subunits that can reversibly assemble and disassemble. This includes oligomeric proteins composed of several smaller monomers, as well as protein complexes assembled from a few proteins. By studying the generic spatial transport properties of such proteins, we investigate here whether their ability to reversibly associate and dissociate may confer on them a functional advantage with respect to nondissociating proteins. In uniform environments with position-independent association-dissociation, we find that enhanced diffusion in the monomeric state coupled to reassociation into the functional oligomeric form leads to enhanced reactivity with localized targets. In nonuniform environments with position-dependent association-dissociation, caused by, for example, spatial gradients of an inhibiting chemical, we find that dissociating proteins generically tend to accumulate in regions where they are most stable, a process that we term "stabilitaxis."
生物学中有许多功能单元，如酶或分子马达，由几个可以可逆组装和拆卸的亚基组成。这包括由几个较小单体组成的寡聚蛋白，以及由少数几种蛋白质组装而成的蛋白质复合物。通过研究此类蛋白质的通用空间输运特性，我们在这里研究了它们可逆缔合和解离的能力是否会赋予它们相对于非解离蛋白质的功能优势。在具有位置无关的缔合-解离的均匀环境中，我们发现单体状态下的扩散增强与功能性寡聚形式的再缔合相结合，导致与局部靶标的反应性增强。在非均匀环境中，例如，由于抑制性化学物质的空间梯度，导致位置依赖的缔合-解离，我们发现，解离的蛋白质通常倾向于在它们最稳定的区域积累，这个过程我们称之为“稳定梯度”。
