The significance of nitrogen cost minimization in proteomes of marine microorganisms

• Published in: The ISME Journal 2012-01, Vol.6 (1), p.71-80
• Main Authors: Grzymski, Joseph J, Dussaq, Alex M
• Format: Article
• Language: English
• Subjects: Adaptations; Amino acids; Amino Acids - metabolism; Bacteria - genetics; Bacteria - metabolism; Biogeochemistry; Biomedical and Life Sciences; Cell size; Codon; Ecological adaptation; Ecology; Energy Metabolism; Evolution; Evolutionary Biology; Genome Size; Genomes; Life Sciences; Marine ecosystems; Marine microorganisms; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microorganisms; Nitrogen; Nitrogen - metabolism; Nutrients; Oceans; Oceans and Seas; Original; original-article; Proteome - metabolism; Seawater - microbiology
• ISSN: 1751-7362; 1751-7370
• DOI: 10.1038/ismej.2011.72

Marine microorganisms thrive under low levels of nitrogen (N). N cost minimization is a major selective pressure imprinted on open-ocean microorganism genomes. Here we show that amino-acid sequences from the open ocean are reduced in N, but increased in average mass compared with coastal-ocean microorganisms. Nutrient limitation exerts significant pressure on organisms supporting the trade-off between N cost minimization and increased average mass of amino acids that is a function of increased A+T codon usage. N cost minimization, especially of highly expressed proteins, reduces the total cellular N budget by 2.7–10%; this minimization in combination with reduction in genome size and cell size is an evolutionary adaptation to nutrient limitation. The biogeochemical and evolutionary precedent for these findings suggests that N limitation is a stronger selective force in the ocean than biosynthetic costs and is an important evolutionary strategy in resource-limited ecosystems.