Abstract：
As the nutrient quality changes, the fractions of ribosomal proteins in the proteome are usually positively correlated with the growth rates due to the auto-catalytic nature of ribosomes. While this growth law is observed across multiple organisms, the relation between the ribosome fraction and growth rate is often more complex than linear, beyond models assuming a constant translation speed. Here, we propose a general framework of protein synthesis considering heterogeneous translation speeds and protein degradations. We demonstrate that the growth law curves are generally environment-specific, e.g., depending on the correlation between the translation speeds and ribosome allocations among proteins. Our predictions of ribosome fractions agree quantitatively with data of Saccharomyces cerevisiae. Interestingly, we find that the growth law curve of Escherichia coli nevertheless appears universal, which we prove must exhibit an upward bending in slow-growth conditions, in agreement with experiments. Our work provides insights on the connection between the heterogeneity among genes and the environment-specificity of cell behaviors.
摘要：
随着营养质量的变化，由于核糖体的自催化性质，蛋白质组中核糖体蛋白的分数通常与生长速率呈正相关。虽然这种生长规律在多种生物中观察到，核糖体分数和生长速率之间的关系通常比线性更复杂，超出了假设平移速度恒定的模型。这里,我们提出了一个考虑异质翻译速度和蛋白质降解的蛋白质合成的一般框架。我们证明了生长规律曲线通常是特定于环境的，例如，取决于蛋白质之间的翻译速度和核糖体分配之间的相关性。我们对核糖体部分的预测与酿酒酵母的数据定量一致。有趣的是,我们发现大肠杆菌的生长规律曲线仍然具有普遍性，我们证明在缓慢生长的条件下必须表现出向上的弯曲，与实验一致。我们的工作提供了有关基因异质性与细胞行为的环境特异性之间联系的见解。
