TY - JOUR
T1 - Saccharomyces cerevisiae Ski7 Is a GTP-Binding Protein Adopting the Characteristic Conformation of Active Translational GTPases
AU - Kowalinski, Eva
AU - Schuller, Anthony
AU - Green, Rachel
AU - Conti, Elena
N1 - Funding Information:
We thank the Max Planck Institute of Biochemistry (MPIB) Crystallization Facility, Biophysics Facility, and the Core Facility; the beamline scientists at PXII and PXIII at SLS for assistance with data collection and members of our laboratories for useful discussions and critical reading of the manuscript. This study was supported by the Max Planck Gesellschaft, the European Commission (ERC Advanced Investigator Grant 294371 and Marie Curie ITN RNPnet) and the Deutsche Forschungsgemeinschaft (DFG SFB646, SFB1035, GRK1721, FOR1680 and CIPSM) to E.C.; by EMBO long-term fellowship, Marie Curie Actions Intra-European Fellowship (I.E.F.) and a Daimler-Benz Postdoctoral stipend to E.K.; R.G. was supported by the NIH and Howard Hughes Medical Institute.
Publisher Copyright:
© 2015 The Authors.
PY - 2015/7/9
Y1 - 2015/7/9
N2 - Summary Ski7 is a cofactor of the cytoplasmic exosome in budding yeast, functioning in both mRNA turnover and non-stop decay (NSD), a surveillance pathway that degrades faulty mRNAs lacking a stop codon. The C-terminal region of Ski7 (Ski7C) shares overall sequence similarity with the translational GTPase (trGTPase) Hbs1, but whether Ski7 has retained the properties of a trGTPase is unclear. Here, we report the high-resolution structures of Ski7C bound to either intact guanosine triphosphate (GTP) or guanosine diphosphate-Pi. The individual domains of Ski7C adopt the conformation characteristic of active trGTPases. Furthermore, the nucleotide-binding site of Ski7C shares similar features compared with active trGTPases, notably the presence of a characteristic monovalent cation. However, a suboptimal polar residue at the putative catalytic site and an unusual polar residue that interacts with the γ-phosphate of GTP distinguish Ski7 from other trGTPases, suggesting it might function rather as a GTP-binding protein than as a GTP-hydrolyzing enzyme.
AB - Summary Ski7 is a cofactor of the cytoplasmic exosome in budding yeast, functioning in both mRNA turnover and non-stop decay (NSD), a surveillance pathway that degrades faulty mRNAs lacking a stop codon. The C-terminal region of Ski7 (Ski7C) shares overall sequence similarity with the translational GTPase (trGTPase) Hbs1, but whether Ski7 has retained the properties of a trGTPase is unclear. Here, we report the high-resolution structures of Ski7C bound to either intact guanosine triphosphate (GTP) or guanosine diphosphate-Pi. The individual domains of Ski7C adopt the conformation characteristic of active trGTPases. Furthermore, the nucleotide-binding site of Ski7C shares similar features compared with active trGTPases, notably the presence of a characteristic monovalent cation. However, a suboptimal polar residue at the putative catalytic site and an unusual polar residue that interacts with the γ-phosphate of GTP distinguish Ski7 from other trGTPases, suggesting it might function rather as a GTP-binding protein than as a GTP-hydrolyzing enzyme.
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U2 - 10.1016/j.str.2015.04.018
DO - 10.1016/j.str.2015.04.018
M3 - Article
C2 - 26051716
AN - SCOPUS:84936847213
SN - 0969-2126
VL - 23
SP - 1336
EP - 1343
JO - Structure
JF - Structure
IS - 7
M1 - 3180
ER -