Biological Complexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan.
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Phys Rev Lett. 2019 Jul 19;123(3):038101. doi: 10.1103/PhysRevLett.123.038101.
Synthesis of biopolymers such as DNA, RNA, and proteins are biophysical processes aided by enzymes. The performance of these enzymes is usually characterized in terms of their average error rate and speed. However, because of thermal fluctuations in these single-molecule processes, both error and speed are inherently stochastic quantities. In this Letter, we study fluctuations of error and speed in biopolymer synthesis and show that they are in general correlated. This means that, under equal conditions, polymers that are synthesized faster due to a fluctuation tend to have either better or worse errors than the average. The error-correction mechanism implemented by the enzyme determines which of the two cases holds. For example, discrimination in the forward reaction rates tends to grant smaller errors to polymers with faster synthesis. The opposite occurs for discrimination in monomer rejection rates. Our results provide an experimentally feasible way to identify error-correction mechanisms by measuring the error-speed correlations.
生物聚合物（如 DNA、RNA 和蛋白质）的合成是由酶辅助的生物物理过程。这些酶的性能通常根据其平均错误率和速度来描述。然而，由于这些单分子过程中的热涨落，错误和速度本质上都是随机的。在这封信中，我们研究了生物聚合物合成中的错误和速度波动，结果表明它们通常是相关的。这意味着，在相同的条件下，由于波动而导致合成速度更快的聚合物，其错误要么比平均水平更好，要么更差。酶所实施的纠错机制决定了哪种情况成立。例如，在正向反应速率上的差异往往会赋予合成速度更快的聚合物更小的错误。对于单体排斥率上的差异则相反。我们的结果通过测量误差-速度相关性，提供了一种可行的实验方法来识别纠错机制。
