Work

Measuring the dynamics of E. coli ribosome biogenesis using pulse-labeling and quantitative mass spectrometry

Year: 2012

Type: article

Abstract: The ribosome is an essential organelle responsible for cellular protein synthesis. Until recently, the study of ribosome assembly has been largely limited to in vitro assays, with few attempts to reconcile these results with the more complex ribosome biogenesis process inside the living cell. Here, we characterize the ribosome synthesis and assembly pathway for each of the E. coli ribosomal protein (r-protein) in vivo using a stable isotope pulse-labeling timecourse. Isotope incorporation into assembled ribosomes was measured by quantitative mass spectrometry (qMS) and fit using steady-state flux models. Most r-proteins exhibit precursor pools ranging in size from 0% to 7% of completed ribosomes, and the sizes of these individual r-protein pools correlate well with the order of r-protein binding in vitro. Additionally, we observe anomalously large precursor pools for specific r-proteins with known extra-ribosomal functions, as well as three r-proteins that apparently turnover during steady-state growth. Taken together, this highly precise, time-dependent proteomic qMS approach should prove useful in future studies of ribosome biogenesis and could be easily extended to explore other complex biological processes in a cellular context.

Source: Molecular BioSystems

DOI: 10.1039/c2mb25310k

Authors: Stephen S Chen, Edit Sperling, Josh M Silverman, Joseph H Davis, James R Williamson

Institution: Scripps Research Institute

Language: English

Topic: RNA and protein synthesis mechanisms

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funder: National Institute of General Medical Sciences

Award: Assembly of E. coli ribosomes in vitro and in cells