Selenocysteine tRNA-specific elongation factor SelB is a structural chimaera of elongation and initiation factors
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Selenocysteine tRNA-specific elongation factor SelB is a structural chimaera of elongation and initiation factors.
In all three kingdoms of life, SelB is a specialized translation elongation factor responsible for the cotranslational incorporation of selenocysteine into proteins by recoding of a UGA stop codon in the presence of a downstream mRNA hairpin loop. Here, we present the X-ray structures of SelB from the archaeon Methanococcus maripaludis in the apo-, GDP- and GppNHp-bound form and use mutational ...
متن کاملCrystal structure of the full-length bacterial selenocysteine-specific elongation factor SelB
Selenocysteine (Sec), the 21(st) amino acid in translation, uses its specific tRNA (tRNA(Sec)) to recognize the UGA codon. The Sec-specific elongation factor SelB brings the selenocysteinyl-tRNA(Sec) (Sec-tRNA(Sec)) to the ribosome, dependent on both an in-frame UGA and a Sec-insertion sequence (SECIS) in the mRNA. The bacterial SelB binds mRNA through its C-terminal region, for which crystal s...
متن کاملInteraction of a selenocysteine-incorporating tRNA with elongation factor Tu from E.coli.
Selenocysteine-incorporating tRNA(Sec)(UCA), the product of selC, was isolated from E.coli and aminoacylated with serine. The equilibrium dissociation constant for the interaction of Ser-tRNA(Sec)(UCA) with elongation factor Tu.GTP was determined to be 5.0 +/- 2.5 x 10(-8) M. Compared with the dissociation constants of the two elongator Ser-tRNA(Ser) species (Kd = 7 x 10(-10) M), the selenocyst...
متن کاملInteraction of mitochondrial elongation factor Tu with aminoacyl-tRNA and elongation factor Ts.
Elongation factor (EF) Tu promotes the binding of aminoacyl-tRNA (aa-tRNA) to the acceptor site of the ribosome. This process requires the formation of a ternary complex (EF-Tu.GTP.aa-tRNA). EF-Tu is released from the ribosome as an EF-Tu.GDP complex. Exchange of GDP for GTP is carried out through the formation of a complex with EF-Ts (EF-Tu.Ts). Mammalian mitochondrial EF-Tu (EF-Tu(mt)) differ...
متن کاملThe Selenocysteine-Specific Elongation Factor Contains Unique Sequences That Are Required for Both Nuclear Export and Selenocysteine Incorporation
Selenocysteine (Sec) is a critical residue in at least 25 human proteins that are essential for antioxidant defense and redox signaling in cells. Sec is inserted into proteins cotranslationally by the recoding of an in-frame UGA termination codon to a Sec codon. In eukaryotes, this recoding event requires several specialized factors, including a dedicated, Sec-specific elongation factor called ...
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ژورنال
عنوان ژورنال: The EMBO Journal
سال: 2004
ISSN: 0261-4189,1460-2075
DOI: 10.1038/sj.emboj.7600505