Skip Navigation



Nucleic Acids Research Advance Access published online on January 3, 2008
Nucleic Acids Research, doi:10.1093/nar/gkm1134
This Article
Right arrow Full Text Freely available
Right arrow Print PDF (7499K) Freely available
Right arrow Screen PDF (909K) Freely available
Right arrow Supplementary Data
Right arrowOA All Versions of this Article:
36/4/1247    most recent
gkm1134v2
gkm1134v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Lynn Sherrer, R.
Right arrow Articles by Söll, D.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lynn Sherrer, R.
Right arrow Articles by Söll, D.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Nucleic Acid Enzymes

Characterization and evolutionary history of an archaeal kinase involved in selenocysteinyl-tRNA formation

R. Lynn Sherrer1, Patrick O’Donoghue1 and Dieter Söll1,2,*

1Department of Molecular Biophysics and Department of Biochemistry and 2Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA

*To whom correspondence should be addressed. Tel: +1 203 432 6200; Fax: +1 203 432 6202: Email: dieter.soll{at}yale.edu

Received November 17, 2007. Revised December 4, 2007. Accepted December 5, 2007.

Selenocysteine (Sec)-decoding archaea and eukaryotes employ a unique route of Sec-tRNASec synthesis in which O-phosphoseryl-tRNASec kinase (PSTK) phosphorylates Ser-tRNASec to produce the O-phosphoseryl-tRNASec (Sep-tRNASec) substrate that Sep-tRNA:Sec-tRNA synthase (SepSecS) converts to Sec-tRNASec. This study presents a biochemical characterization of Methanocaldococcus jannaschii PSTK, including kinetics of Sep-tRNASec formation (Km for Ser-tRNASec of 40 nM and ATP of 2.6 mM). PSTK binds both Ser-tRNASec and tRNASec with high affinity (Kd values of 53 nM and 39 nM, respectively). The ATPase activity of PSTK may be activated via an induced fit mechanism in which binding of tRNASec specifically stimulates hydrolysis. Albeit with lower activity than ATP, PSTK utilizes GTP, CTP, UTP and dATP as phosphate-donors. Homology with related kinases allowed prediction of the ATPase active site, comprised of phosphate-binding loop (P-loop), Walker B and RxxxR motifs. Gly14, Lys17, Ser18, Asp41, Arg116 and Arg120 mutations resulted in enzymes with decreased activity highlighting the importance of these conserved motifs in PSTK catalysis both in vivo and in vitro. Phylogenetic analysis of PSTK in the context of its ‘DxTN’ kinase family shows that PSTK co-evolved precisely with SepSecS and indicates the presence of a previously unidentified PSTK in Plasmodium species.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.