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Eukaryotic selenocysteine tRNA has the 9/4 secondary structure
Author(s) -
Mizutani Takaharu,
Goto Chiharu
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01104-2
Subject(s) - transfer rna , protein secondary structure , selenocysteine , mutant , chemistry , stacking , stereochemistry , crystallography , biology , biochemistry , enzyme , rna , gene , organic chemistry , cysteine
There are two secondary structure models for the eukaryotic selenocysteine (Sec) tRNA Sec . One model, the 9/4 structure, was experimentally tested and possesses acceptor and T‐stems with 9 and 4 bp, respectively [Sturchler et al., 1993; Hubert et al., 1998]. The other one, the 7/5 secondary structure with a bulge in the T‐stem, was derived from theoretical calculation [Ioudovitch and Steinberg, 1999]. In this report, we show more experimental results supporting the 9/4 secondary structure. Several tRNA Sec mutants, whose secondary structure can adopt only the 9/4 structure, were active for serylation and selenylation. Some mutants that cannot base‐pair between positions 26 and 44 to provide the 6 bp anticodon stem were still active, inconsistent with the model by Steinberg. We also show that the orientation of the V‐arm directly or indirectly influences the selenylation activity, and that the rigid 6 bp D‐stem is important. Finally, we conclude that all tRNAs Sec possess the 13 bp domain II made by the stacking of the colinear AA and T‐stems, whether they present the 9/4 structure in Eukarya and Archaea or the 8/5 structure in bacteria.