The algal selenoproteomes
Abstract Background: Selenium is an important trace element, and selenocysteine is its predominant form in vivo. The protein containing selenocysteine is selenoprotein, whose special structural features include not only the TGA codon encoding selenocysteine, but also the SECIS element in mRNA and the conservation of selenocysteine flanking region. These special features have led to the development of a series of bioinformatics methods for the prediction and research of selenoprotein genes. There are some studies and reports on the evolution and distribution of selenoprotein genes in prokaryotes and multicellular eukaryotes, but the systematic analysis of single-cell eukaryotes, especially algae, is very limited. Results: In this study, we predicted selenoprotein genes in 137 species of algae by using a program we previously developed. More than 1000 selenoprotein genes were obtained. A database website was built to hold these algae selenoprotein genes (www.selenoprotein.com). These genes belong to 42 selenoprotein families, including three novel selenoprotein gene families. Conclusions: This study reveals the primordial state of the eukaryotic selenoproteome. It is an important clue to explore the significance of selenium for primordial eukaryotes and to build the whole evolutionary spectrum of selenoproteins for all life.