Description:
Selenoproteins, such as SELK, contain the rare twenty-first amino acid, selenocysteine (sec). These proteins lack common amino acid sequence motifs, but the 3-prime untranslated regions of selenoprotein genes have a common stem-loop structure, the sec insertion sequence (SECIS), that is necessary for the recognition of UGA as a sec codon rather than as a stop signal.[supplied by OMIM]