Molecular insights into protein synthesis with proline residues.
Proline is an amino acid with a unique cyclic structure that facilitates the folding of many proteins, but also impedes the rate of peptide bond formation by the ribosome. As a ribosome substrate, proline reacts markedly slower when compared with other amino acids both as a donor and as an acceptor of the nascent peptide. Furthermore, synthesis of peptides with consecutive proline residues triggers ribosome stalling. Here, we report crystal structures of the eukaryotic ribosome bound to analogs of mono- and diprolyl-tRNAs. These structures provide a high-resolution insight into unique properties of proline as a ribosome substrate. They show that the cyclic structure of proline residue prevents proline positioning in the amino acid binding pocket and affects the nascent peptide chain position in the ribosomal peptide exit tunnel. These observations extend current knowledge of the protein synthesis mechanism. They also revise an old dogma that amino acids bind the ribosomal active site in a uniform way by showing that proline has a binding mode distinct from other amino acids.
Institute of Genetics and Molecular and Cellular Biology CNRS UMR7104 INSERM UMR964, Illkirch, France.|Strasbourg University, Strasbourg, France.
Sergey
S
Melnikov
Institute of Genetics and Molecular and Cellular Biology CNRS UMR7104 INSERM UMR964, Illkirch, France.|Strasbourg University, Strasbourg, France.
Justine
0000-0002-1026-542X
J
Mailliot
Institute of Organic Chemistry Leopold Franzens University, Innsbruck, Austria.
Lukas
L
Rigger
Institute of Organic Chemistry Leopold Franzens University, Innsbruck, Austria.
Sandro
S
Neuner
Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Bethesda, MD, USA.
Byung-Sik
BS
Shin
Institute of Genetics and Molecular and Cellular Biology CNRS UMR7104 INSERM UMR964, Illkirch, France.|Strasbourg University, Strasbourg, France.
Gulnara
G
Yusupova
Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Bethesda, MD, USA thomas.dever@nih.gov ronald.micura@uibk.ac.at marat@igbmc.fr.
Thomas E
TE
Dever
Institute of Organic Chemistry Leopold Franzens University, Innsbruck, Austria thomas.dever@nih.gov ronald.micura@uibk.ac.at marat@igbmc.fr.
Ronald
R
Micura
Institute of Genetics and Molecular and Cellular Biology CNRS UMR7104 INSERM UMR964, Illkirch, France thomas.dever@nih.gov ronald.micura@uibk.ac.at marat@igbmc.fr.|Strasbourg University, Strasbourg, France.
Marat
M
Yusupov
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011392:Proline / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D012361:RNA, Transfer, Pro / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism
D010455:Peptides; D012361:RNA, Transfer, Pro; D011392:Proline
hydrolysis‐resistant aminoacyl‐tRNA analogs; peptide bond formation; proline; protein synthesis; ribosome