In a new paper, we study whether E. coli can optimise its ribosome concentration — to not have too many and too few ribosomes expressed — to safe resources for the synthesis of other growth-associated proteins. We think that this is a mechanism that allows E. coli to maximise its growth rate. Whether it reaches this maximum, we do not yet know. We do however show that the ppGpp regulation mechanism is in principle capable of optimising the ribosome level. If similar mechanisms are associated with the gene expression of other metabolic proteins then E. coli might regulate its metabolic genes in an optimal manner that maximises its growth rate. An explanation for this behaviour would be that growth rate is often under natural selection. Several other papers, by the Swain lab and the Hwa lab, are indicating related findings. In this paper, and in some of our recent others, we therefore relate a molecular-regulation mechanism to a fitness-maximisation strategy. We are particularly interested in such relations as those as explain why regulation of metabolism is the way that it is. The classical mechanistic view of systems biology does not answer the why question, it answers the how question. We think that those views should be merged leading to more interactions between microbial evolution and molecular-systems biology.
- A new publication about genome-scale modelling was published!
- We have just had a very successful lab retreat!