Abstract
Selenoproteins are a group of proteins that contain at least one amino acid named selenocysteine (Sec). Its chemical structure consists of a cysteine residue in which the sulphur atom of the thiol group is replaced by a selenium. Unlike the rest of amino acids, no selenocysteine is accumulated inside the cells due to its high reactivity. However, it gets stored as H2Se, the less reactive selenide form. This selenium pool is required for Sec synthesis as well as other proteins involved in UGA codon recognition for Sec incorporation to the peptide chain, although it is usually used for protein termination. Indeed, it is precisely for this dual role that investigation of selenoproteins is such a complex task. Even many species genomes have been incorrectly annotated, many in silico tools have been developed in the last years in order to recognise selenoproteins in new sequenced genomes. In the present study we have identified the selenoproteins from Manis javanica by comparing its genome with the one from Homo sapiens, a very close species. Our results show 21 selenoproteins, 5 cysteine-homologue proteins and 7 proteins involved in Sec synthesis. It represents a loss of some selenoproteins and cysteine-homologue proteins and the same amount of machinery proteins. This project aims to provide a phylogenetic approach for some selenoprotein families involved in the genome of Manis javanica.