کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2048119 1074063 2012 4 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mutational analysis of Sep-tRNA:Cys-tRNA synthase reveals critical residues for tRNA-dependent cysteine formation
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Mutational analysis of Sep-tRNA:Cys-tRNA synthase reveals critical residues for tRNA-dependent cysteine formation
چکیده انگلیسی

In methanogenic archaea, Sep-tRNA:Cys-tRNA synthase (SepCysS) converts Sep-tRNACys to Cys-tRNACys. The mechanism of tRNA-dependent cysteine formation remains unclear due to the lack of functional studies. In this work, we mutated 19 conserved residues in Methanocaldococcus jannaschii SepCysS, and employed an in vivo system to determine the activity of the resulting variants. Our results show that three active-site cysteines (Cys39, Cys42 and Cys247) are essential for SepCysS activity. In addition, combined with structural modeling, our mutational and functional analyses also reveal multiple residues that are important for the binding of PLP, Sep and tRNA. Our work thus represents the first systematic functional analysis of conserved residues in archaeal SepCysSs, providing insights into the catalytic and substrate binding mechanisms of this poorly characterized enzyme.


► Mutational and functional studies identified 11 residues critical for SepCysS activity.
► All three active site cysteines of SepCysS are essential for tRNA-dependent Cys formation.
► The phosphate group of Sep is recognized by Arg79, His103 and Tyr104.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: FEBS Letters - Volume 586, Issue 1, 2 January 2012, Pages 60–63
نویسندگان
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