Proteome Remodeling in Response to Sulfur Limitation in “ Candidatus Pelagibacter ubique”

Smith et al. (2016). mSystems 1 (4)
Names (1)
Ca. Pelagibacter ubique
Biochemistry Computer Science Applications Ecology, Evolution, Behavior and Systematics Genetics Microbiology Modelling and Simulation Molecular Biology Physiology
“ Ca . Pelagibacter ubique” is a key driver of marine biogeochemistry cycles and a model for understanding how minimal genomes evolved in free-living anucleate organisms. This study explores the unusual sulfur acquisition strategy that has evolved in these cells, which lack assimilatory sulfate reduction and instead rely on reduced sulfur compounds found in oxic marine environments to meet their cellular quotas. Our findings demonstrate that the sulfur acquisition systems are constitutively expressed but the enzymatic steps leading to the essential sulfur-containing amino acid methionine are regulated by a unique array of riboswitches and genes, many of which are encoded in a rapidly evolving genome region. These findings support mounting evidence that streamlined cells have evolved regulatory mechanisms that minimize transcriptional switching and, unexpectedly, localize essential sulfur acquisition genes in a genome region normally associated with adaption to environmental variation.
Publication date