Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom.
Phys Rev Lett. 2009 Oct 9;103(15):158101. doi: 10.1103/PhysRevLett.103.158101. Epub 2009 Oct 7.
The accuracy by which biological cells sense chemical concentration is ultimately limited by the random arrival of particles at the receptors by diffusion. This fundamental physical limit is generally considered to be the Berg-Purcell limit [Biophys. J. 20, 193 (1977)]. Here we derive a lower limit by applying maximum likelihood to the time series of receptor occupancy. The increased accuracy stems from solely considering the unoccupied time intervals--disregarding the occupied time intervals as these do not contain any information about the external particle concentration, and only decrease the accuracy of the concentration estimate. Receptors which minimize the bound time intervals achieve the highest possible accuracy. We discuss how a cell could implement such an optimal sensing strategy by absorbing or degrading bound particles.
生物细胞感知化学浓度的准确性最终受到扩散作用下粒子随机到达受体的限制。这个基本的物理限制通常被认为是 Berg-Purcell 限制[Biophys. J. 20, 193 (1977)]。在这里，我们通过对受体占有率的时间序列应用最大似然法得到了一个下限。这种精度的提高仅源于仅考虑未被占据的时间间隔——忽略已被占据的时间间隔，因为这些时间间隔不包含任何关于外部粒子浓度的信息，而且仅会降低浓度估计的准确性。使绑定时间间隔最小化的受体可实现尽可能高的准确性。我们讨论了细胞如何通过吸收或降解绑定的粒子来实现这种最优的传感策略。
