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A tRNA‐dependent cysteine biosynthesis enzyme recognizes the selenocysteine‐specific tRNA in Escherichia coli
Author(s) -
Yuan Jing,
Hohn Michael J.,
Sherrer R. Lynn,
Palioura Sotiria,
Su Dan,
Söll Dieter
Publication year - 2010
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/j.febslet.2010.05.028
Subject(s) - transfer rna , selenocysteine , biochemistry , t arm , escherichia coli , enzyme , cysteine , amino acid , biology , chemistry , rna , gene
The essential methanogen enzyme Sep‐tRNA:Cys‐tRNA synthase (SepCysS) converts O ‐phosphoseryl‐tRNA Cys (Sep‐tRNA Cys ) into Cys‐tRNA Cys in the presence of a sulfur donor. Likewise, Sep‐tRNA:Sec‐tRNA synthase converts O ‐phosphoseryl‐tRNA Sec (Sep‐tRNA Sec ) to selenocysteinyl‐tRNA Sec (Sec‐tRNA Sec ) using a selenium donor. While the Sep moiety of the aminoacyl‐tRNA substrates is the same in both reactions, tRNA Cys and tRNA Sec differ greatly in sequence and structure. In an Escherichia coli genetic approach that tests for formate dehydrogenase activity in the absence of selenium donor we show that Sep‐tRNA Sec is a substrate for SepCysS. Since Sec and Cys are the only active site amino acids known to sustain FDH activity, we conclude that SepCysS converts Sep‐tRNA Sec to Cys‐tRNA Sec , and that Sep is crucial for SepCysS recognition.