Proteome-wide alterations in Escherichia coli translation rates upon anaerobiosis.
Enzyme reprofiling in bacteria during adaptation from one environmental condition to another may be regulated by both transcription and translation. However, little is known about the contribution of translational regulation. Recently, we have developed a pulse labeling method using the methionine analog azidohomoalanine to determine the relative amounts of proteins synthesized by Escherichia coli in a brief time frame upon a change in environmental conditions. Here we present an extension of our analytical strategy, which entails measuring changes in total protein levels on the same time scale as new protein synthesis. This allows identification of stable and labile proteins and demonstrates that altered levels of most newly synthesized proteins are the result of a change in translation rate rather than degradation rate. With this extended strategy, average relative translation rates for 10 min immediately after a switch from aerobiosis to anaerobiosis were determined. The majority of proteins with increased synthesis rates upon an anaerobic switch are involved in glycolysis and pathways aimed at preventing glycolysis grinding to a halt by a cellular redox imbalance. Our method can be used to compare relative translation rates with relative mRNA levels at the same time. Discrepancies between these parameters may reveal genes whose expression is regulated by translation rather than by transcription. This may help unravel molecular mechanism underlying changes in translation rates, e.g. mediated by small regulatory RNAs.
Kramer
Gertjan
G
Mass Spectrometry of Biomacromoleculesm, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Kruislaan 904, Amsterdam, The Netherlands.
Sprenger
Richard R
RR
Nessen
Merel A
MA
Roseboom
Winfried
W
Speijer
Dave
D
de Jong
Luitzen
L
de Mattos
M Joost Teixeira
MJ
Back
JaapWillem
J
de Koster
Chris G
CG
D000409:Alanine / Q000031:analogs & derivatives / Q000378:metabolism; D000693:Anaerobiosis / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D014176:Protein Biosynthesis; D020543:Proteome / Q000235:genetics / Q000378:metabolism
D029968:Escherichia coli Proteins; D020543:Proteome; C506098:azidohomoalanine; D000409:Alanine