Identify New Selenoproteins in Emiliania Huxleyi Genome

Selenium plays an important biological role in the expression of the functions of proteins, such as reproduction, immune function and disease resistance. A selenoprotein includes an amino acid called selenocysteine (Sec) which is known as the 21st amino acid. “‘Sec’ is a selenium-containing amino acid that is co-translationally inserted into nascent polypeptide by recording ‘UGA’ codons.” In previous works, 48 selenoproteins found in the Emiliania huxleyi genome. The object of this research was to apply recently developed selenoprotein prediction programs to identify additional unknown selenoproteins in Emiliania huxleyi genome. We matched the Emiliania huxleyi genome to the amino acid sequence alignments of all known eukaryotic selenoprotein families in the Selenoprofiles program, and 341 predicted selenoproteins were generated. There were 145 out of 341 predicted selenoproteins that had selenocysteine insertion sequences, which were generated by the SECISearch3 program. There were several similar sequences that existed in the 145 predicted selenoproteins. We removed the duplicates which had 95% similarity in their sequences. After removing the duplicates there were 85 selenoproteins in which 33 of the them were recognized by the Seblastian program and the other 52 could not be identified by Seblastian. Among 33 proteins that were identified by Seblastian, 28 of them were among the 48 sequences that were generated in the previous work and the other 5 were new. The other 52 sequences that were recognized by SECISearch3 but could not be identified by Seblastian are potential selenoproteins that can be further investigated in future work.