Gene-Wei Li (UCSF)
Quantitative & Computational Biology Seminar Series
University of California, San Francisco
A quantitative view of the bacterial proteome
Protein biosynthesis is the biggest consumer of cellular energy during proliferation. The composition of the proteome is therefore tightly regulated in order to achieve efficient use of ribosome. At UCSF, I have made several key discoveries revealing how bacteria precisely control the speed of protein synthesis. First, I found that, contrary to current dogma, translation rate in vivo is independent of codon usage. Instead, pervasive ribosome pausing throughout the transcriptome is driven by internal Shine-Dalgarno sequences. This observation provides critical insights into the selection of coding sequences. Second, by developing a method to quantify the absolute rate of protein synthesis for nearly all genes in bacteria, I showed that many proteins have precisely controlled expression levels that quantitatively reflect their functions and the cell's physiology. This set of methods and genome-wide data provides a unique way to broadly characterize many specific cellular processes, from design principles of transcriptional regulation to metabolic pathways.
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