@article{9d94acf0c0b647bb8cde119890bbac0c,
title = "Uniformity of Peptide Release Is Maintained by Methylation of Release Factors",
abstract = "Termination of protein synthesis on the ribosome is catalyzed by release factors (RFs), which share a conserved glycine-glycine-glutamine (GGQ) motif. The glutamine residue is methylated in vivo, but a mechanistic understanding of its contribution to hydrolysis is lacking. Here, we show that the modification, apart from increasing the overall rate of termination on all dipeptides, substantially increases the rate of peptide release on a subset of amino acids. In the presence of unmethylated RFs, we measure rates of hydrolysis that are exceptionally slow on proline and glycine residues and approximately two orders of magnitude faster in the presence of the methylated factors. Structures of 70S ribosomes bound to methylated RF1 and RF2 reveal that the glutamine side-chain methylation packs against 23S rRNA nucleotide 2451, stabilizing the GGQ motif and placing the side-chain amide of the glutamine toward tRNA. These data provide a framework for understanding how release factor modifications impact termination.",
keywords = "methylation, peptide release, release factor, ribosome, termination, translation",
author = "Pierson, {William E.} and Hoffer, {Eric D.} and Keedy, {Hannah E.} and Simms, {Carrie L.} and Dunham, {Christine M.} and Zaher, {Hani S.}",
note = "Funding Information: The authors wish to thank Joe Jez and Doug Chalker for comments on an earlier version of the manuscript and members of the H.S.Z. and C.M.D. laboratories for useful discussions. This work was supported by the NIH (NIH R01GM093278 to C.M.D. and R01GM112641 to H.S.Z.), a Searle Scholars award (to H.S.Z.), and a Pew Scholar in the Biomedical Sciences award (to C.M.D.). The Donald Danforth Plant Science Center Proteomics and Mass Spectrometry Facility is supported the National Science Foundation grant no. DBI-0922879 for acquisition of the LTQ-Velos Pro Orbitrap LC-MS/MS. The Emory Integrated Proteomics Core is supported by the Neuroscience NINDS Core Facilities (P30NS055077), the Emory University School of Medicine, and is one of the Emory Integrated Core Facilities. The X-ray crystallography datasets were collected at the NE-CAT beamlines, which are funded by the National Institute of General Medical Sciences from the NIH (P41 GM103403), and at the SER-CAT beamlines. The Pilatus 6M detector on 24-ID-C beam line is funded by a NIH-ORIP HEI grant (S10 RR029205). This research used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. Publisher Copyright: {\textcopyright} 2016 The Author(s)",
year = "2016",
month = sep,
day = "27",
doi = "10.1016/j.celrep.2016.08.085",
language = "English",
volume = "17",
pages = "11--18",
journal = "Cell Reports",
issn = "2211-1247",
number = "1",
}