title: The significance of nitrogen cost minimization in proteomes of marine microorganisms.
abstract: 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.
authors.affiliation: Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV, USA. joeg@dri.edu
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Grzymski
authors.forename: Alex M
authors.initials: AM
authors.lastname: Dussaq
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D003062:Codon; D004734:Energy Metabolism; D059646:Genome Size; D009584:Nitrogen / Q000378:metabolism*; D009792:Oceans and Seas; D020543:Proteome / Q000378:metabolism; D012623:Seawater / Q000382:microbiology*
chemical_list: D000596:Amino Acids; D003062:Codon; D020543:Proteome; D009584:Nitrogen