Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. This aminoacid is cotranslationally i...Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. This aminoacid is cotranslationally incorporated at UGA codons which usually act as translation stop codons. In eukaryotes, decoding of selenocysteine necessitates the participation of the selenocysteine insertion sequence (SECIS), an element lying in the 3' -untranslated region of selenoprotein mRNAs. A detailed experimental study of the secondary structures of the SECIS elements of rat and human type 1 iodothyronine deiodinases and rat glutathione peroxidase was performed. Enzymatic and chemical structure probing led us to propose a secondary structure model, supported by sequence comparison of 23 SECIS mRNAs. The secondary structure model revealed the existence of a novel type of RNA motif composed of four consecutive non-Watson-Crick base-pairs. Using gel shift experiments, we identified in several mammalian cell type extracts the protein SBP,for SECIS-binding protein, that specifically recognizes the iodothyronine deiodinases and glutathione peroxidase SECIS elements. The structural model that we derived for the SECIS RNAs discloses RNA features possibly implicated in the binding of SBP and/or SECIS function展开更多
The year 2025 marked the inaugural volume of Artificial Intelligence Science and Engineering(AISE).Withthe strong support of the global academic community in artificial intelligence and control science,and through the...The year 2025 marked the inaugural volume of Artificial Intelligence Science and Engineering(AISE).Withthe strong support of the global academic community in artificial intelligence and control science,and through thededicated efforts of our editorial board members,authors,and reviewers,all four issues were successfullypublished.These issues brought together significant original contributions and authoritative surveys from leadingscholars,laying a solid academic foundation for the long-term development of the journal.展开更多
文摘Selenocysteine, a selenium-containing analog of cysteine, is found in the prokaryotic and eukaryotic kingdoms in active sites of enzymes involved in oxidation-reduction reactions. This aminoacid is cotranslationally incorporated at UGA codons which usually act as translation stop codons. In eukaryotes, decoding of selenocysteine necessitates the participation of the selenocysteine insertion sequence (SECIS), an element lying in the 3' -untranslated region of selenoprotein mRNAs. A detailed experimental study of the secondary structures of the SECIS elements of rat and human type 1 iodothyronine deiodinases and rat glutathione peroxidase was performed. Enzymatic and chemical structure probing led us to propose a secondary structure model, supported by sequence comparison of 23 SECIS mRNAs. The secondary structure model revealed the existence of a novel type of RNA motif composed of four consecutive non-Watson-Crick base-pairs. Using gel shift experiments, we identified in several mammalian cell type extracts the protein SBP,for SECIS-binding protein, that specifically recognizes the iodothyronine deiodinases and glutathione peroxidase SECIS elements. The structural model that we derived for the SECIS RNAs discloses RNA features possibly implicated in the binding of SBP and/or SECIS function
文摘The year 2025 marked the inaugural volume of Artificial Intelligence Science and Engineering(AISE).Withthe strong support of the global academic community in artificial intelligence and control science,and through thededicated efforts of our editorial board members,authors,and reviewers,all four issues were successfullypublished.These issues brought together significant original contributions and authoritative surveys from leadingscholars,laying a solid academic foundation for the long-term development of the journal.
