1
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Wang Q, Su H. A Tale of Water Molecules in the Ribosomal Peptidyl Transferase Reaction. Biochemistry 2022; 61:2241-2247. [PMID: 36178262 DOI: 10.1021/acs.biochem.2c00098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The peptidyl transferase center (PTC) in the large subunit of the ribosome plays a critical role in protein synthesis by catalyzing the formation of peptide bonds with an astounding speed of about 15 to 20 peptide bonds per second. The ribosome coordinates the nucleophilic attack and deprotonation in the rate-limiting step at the PTC. However, the details of peptide bond formation within the ribosome, particularly the precise role of the two water molecules in the PTC, remain unclear. Here, we propose a novel stepwise "proton shuttle" mechanism which corroborates all the reported experimental measurements so far. In this mechanism, a water molecule close to A76 of peptidyl-tRNA 2'- and 3'-O stabilizes the transition state. The other one adjacent to the carbonyl oxygen of peptidyl-tRNA actively participates in the proton shuttle, playing the catalytic role of ribosome-catalyzed peptide bond formation.
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Affiliation(s)
- Qiang Wang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 999077, China
| | - Haibin Su
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 999077, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 999077, China.,HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen 518048, China
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2
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Bao L, Karpenko VV, Forster AC. Rate-limiting hydrolysis in ribosomal release reactions revealed by ester activation. J Biol Chem 2022; 298:102509. [PMID: 36300356 PMCID: PMC9589212 DOI: 10.1016/j.jbc.2022.102509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022] Open
Abstract
Translation terminates by releasing the polypeptide chain in one of two chemical reactions catalyzed by the ribosome. Release is also a target for engineering, as readthrough of a stop codon enables incorporation of unnatural amino acids and treatment of genetic diseases. Hydrolysis of the ester bond of peptidyl-tRNA requires conformational changes of both a class I release factor (RF) protein and the peptidyl transferase center of a large subunit rRNA. The rate-limiting step was proposed to be hydrolysis at physiological pH and an RF conformational change at higher pH, but evidence was indirect. Here, we tested this by activating the ester electrophile at the Escherichia coli ribosomal P site using a trifluorine-substituted amino acid. Quench-flow kinetics revealed that RF1-catalyzed release could be accelerated, but only at pH 6.2-7.7 and not higher pH. This provided direct evidence for rate-limiting hydrolysis at physiological or lower pH and a different rate limitation at higher pH. Additionally, we optimized RF-free release catalyzed by unacylated tRNA or the CCA trinucleotide (in 30% acetone). We determined that these two model release reactions, although very slow, were surprisingly accelerated by the trifluorine analog but to a different extent from each other and from RF-catalyzed release. Hence, hydrolysis was rate limiting in all three reactions. Furthermore, in 20% ethanol, we found that there was significant competition between fMet-ethyl ester formation and release in all three release reactions. We thus favor proposed mechanisms for translation termination that do not require a fully-negatively-charged OH− nucleophile.
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3
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Tirumalai MR, Rivas M, Tran Q, Fox GE. The Peptidyl Transferase Center: a Window to the Past. Microbiol Mol Biol Rev 2021; 85:e0010421. [PMID: 34756086 PMCID: PMC8579967 DOI: 10.1128/mmbr.00104-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In his 2001 article, "Translation: in retrospect and prospect," the late Carl Woese made a prescient observation that there was a need for the then-current view of translation to be "reformulated to become an all-embracing perspective about which 21st century Biology can develop" (RNA 7:1055-1067, 2001, https://doi.org/10.1017/s1355838201010615). The quest to decipher the origins of life and the road to the genetic code are both inextricably linked with the history of the ribosome. After over 60 years of research, significant progress in our understanding of how ribosomes work has been made. Particularly attractive is a model in which the ribosome may facilitate an ∼180° rotation of the CCA end of the tRNA from the A-site to the P-site while the acceptor stem of the tRNA would then undergo a translation from the A-site to the P-site. However, the central question of how the ribosome originated remains unresolved. Along the path from a primitive RNA world or an RNA-peptide world to a proto-ribosome world, the advent of the peptidyl transferase activity would have been a seminal event. This functionality is now housed within a local region of the large-subunit (LSU) rRNA, namely, the peptidyl transferase center (PTC). The PTC is responsible for peptide bond formation during protein synthesis and is usually considered to be the oldest part of the modern ribosome. What is frequently overlooked is that by examining the origins of the PTC itself, one is likely going back even further in time. In this regard, it has been proposed that the modern PTC originated from the association of two smaller RNAs that were once independent and now comprise a pseudosymmetric region in the modern PTC. Could such an association have survived? Recent studies have shown that the extant PTC is largely depleted of ribosomal protein interactions. It is other elements like metallic ion coordination and nonstandard base/base interactions that would have had to stabilize the association of RNAs. Here, we present a detailed review of the literature focused on the nature of the extant PTC and its proposed ancestor, the proto-ribosome.
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Affiliation(s)
- Madhan R. Tirumalai
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Mario Rivas
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Quyen Tran
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - George E. Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
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4
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Balasanyants SM, Aleksandrova EV, Polikanov YS. The Role of Release Factors in the Hydrolysis of Ester Bond in Peptidyl-tRNA. BIOCHEMISTRY (MOSCOW) 2021; 86:1122-1127. [PMID: 34565315 DOI: 10.1134/s0006297921090078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Class I release factors (RFs) recognize stop codons in the sequences of mRNAs and are required for the hydrolysis of peptidyl-tRNA in the ribosomal P site during the final step of protein synthesis in bacteria, resulting in the release of a complete polypeptide chain from the ribosome. A key role in this process belongs to the highly conserved GGQ motif in RFs. Mutations in this motif can reduce the hydrolysis rate or even completely inhibit the reaction. Previously, it was hypothesized that the amino acid residues of GGQ (especially glutamine) are essential for the proper coordination of the water molecule for subsequent hydrolysis of the ester bond. However, available structures of the 70S ribosome termination complex do not allow unambiguous identification of the exact orientation of the carbonyl group in peptidyl-tRNA relative to the GGQ, as well as of the position of the catalytic water molecule in the peptidyl transferase center (PTC). This mini-review summarizes key facts and hypotheses on the role of GGQ in the catalysis of peptide release, as well as suggests and discusses future experiments aimed to produce high-quality structural data for deciphering the precise mechanism of RF-mediated catalysis.
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Affiliation(s)
- Samson M Balasanyants
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Elena V Aleksandrova
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yury S Polikanov
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
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5
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Fukushima K, Esaki H. Theoretical Study of the Mechanism of Ribosomal Peptide Bond Formation Using the ONIOM Method. Chem Pharm Bull (Tokyo) 2021; 69:734-740. [PMID: 34334517 DOI: 10.1248/cpb.c21-00148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peptide bond formation in living cells occurs at the peptidyl transferase center (PTC) of the large ribosomal subunit and involves the transfer of the peptidyl group from peptidyl-tRNA to aminoacyl-tRNA. Despite numerous kinetic and theoretical studies, many details of this reaction -such as whether it proceeds via a stepwise or concerted mechanism- remain unclear. In this study, we calculated the geometry and energy of the transition states and intermediates in peptide bond formation in the PTC environment using the ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) method. The calculations indicated that the energy of the transition states of stepwise mechanisms are lower than those of concerted mechanisms and suggested that the reaction involves a neutral tetrahedral intermediate that is stabilized through the hydrogen-bonding network in the PTC environment. The results will lead to a better understanding of the mechanism of peptidyl transfer reaction, and resolve fundamental questions of the steps and molecular intermediates involved in peptide bond formation in the ribosome.
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6
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D Amino Acids Highlight the Catalytic Power of the Ribosome. Cell Chem Biol 2019; 26:1639-1641. [PMID: 31680066 DOI: 10.1016/j.chembiol.2019.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/06/2019] [Accepted: 10/10/2019] [Indexed: 02/08/2023]
Abstract
The possible mechanism(s) by which ribosomes make peptide bonds during protein synthesis have been explored for decades. Yet, there is no agreement on how the catalytic site, the peptidyl transferase center (PTC), promotes this reaction. Here, we discuss the results of recent investigations of translation with D amino acids that provide fresh insights into that longstanding question.
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7
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Routh SB, Sankaranarayanan R. Enzyme action at RNA–protein interface in DTD-like fold. Curr Opin Struct Biol 2018; 53:107-114. [DOI: 10.1016/j.sbi.2018.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/24/2018] [Accepted: 07/30/2018] [Indexed: 02/08/2023]
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8
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Monajemi H, Md Zain S, Ishida T, Wan Abdullah WAT. Quantum mechanical tunnelling through the catalytic effects of A2451 ribosomal residue during a stepwise peptide bond formation. Biochem Cell Biol 2018; 97:497-503. [PMID: 30444637 DOI: 10.1139/bcb-2018-0220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The search for the mechanism of ribosomal peptide bond formation is still ongoing. Even though the actual mechanism of peptide bod formation is still unknown, the dominance of proton transfer in this reaction is known for certain. Therefore, it is vital to take the quantum mechanical effects on proton transfer reaction into consideration; the effects of which were neglected in all previous studies. In this study, we have taken such effects into consideration using a semi-classical approach to the overall reaction mechanism. The M06-2X density functional with the 6-31++G(d,p) basis set was used to calculate the energies of the critical points on the potential energy surface of the reaction mechanism, which are then used in transition state theory to calculate the classical reaction rate. The tunnelling contribution is then added to the classical part by calculating the transmission permeability and tunnelling constant of the reaction barrier, using the numerical integration over the Boltzmann distribution for the symmetrical Eckart potential. The results of this study, which accounts for quantum effects, indicates that the A2451 ribosomal residue induces proton tunnelling in a stepwise peptide bond formation.
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Affiliation(s)
- Hadieh Monajemi
- a Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Sharifuddin Md Zain
- b Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toshimasa Ishida
- b Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
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9
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Abstract
This review summarizes our current understanding of translation in prokaryotes, focusing on the mechanistic and structural aspects of each phase of translation: initiation, elongation, termination, and ribosome recycling. The assembly of the initiation complex provides multiple checkpoints for messenger RNA (mRNA) and start-site selection. Correct codon-anticodon interaction during the decoding phase of elongation results in major conformational changes of the small ribosomal subunit and shapes the reaction pathway of guanosine triphosphate (GTP) hydrolysis. The ribosome orchestrates proton transfer during peptide bond formation, but requires the help of elongation factor P (EF-P) when two or more consecutive Pro residues are to be incorporated. Understanding the choreography of transfer RNA (tRNA) and mRNA movements during translocation helps to place the available structures of translocation intermediates onto the time axis of the reaction pathway. The nascent protein begins to fold cotranslationally, in the constrained space of the polypeptide exit tunnel of the ribosome. When a stop codon is reached at the end of the coding sequence, the ribosome, assisted by termination factors, hydrolyzes the ester bond of the peptidyl-tRNA, thereby releasing the nascent protein. Following termination, the ribosome is dissociated into subunits and recycled into another round of initiation. At each step of translation, the ribosome undergoes dynamic fluctuations between different conformation states. The aim of this article is to show the link between ribosome structure, dynamics, and function.
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Affiliation(s)
- Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Goettingen 37077, Germany
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10
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Decoding on the ribosome depends on the structure of the mRNA phosphodiester backbone. Proc Natl Acad Sci U S A 2018; 115:E6731-E6740. [PMID: 29967153 DOI: 10.1073/pnas.1721431115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
During translation, the ribosome plays an active role in ensuring that mRNA is decoded accurately and rapidly. Recently, biochemical studies have also implicated certain accessory factors in maintaining decoding accuracy. However, it is currently unclear whether the mRNA itself plays an active role in the process beyond its ability to base pair with the tRNA. Structural studies revealed that the mRNA kinks at the interface of the P and A sites. A magnesium ion appears to stabilize this structure through electrostatic interactions with the phosphodiester backbone of the mRNA. Here we examined the role of the kink structure on decoding using a well-defined in vitro translation system. Disruption of the kink structure through site-specific phosphorothioate modification resulted in an acute hyperaccurate phenotype. We measured rates of peptidyl transfer for near-cognate tRNAs that were severely diminished and in some instances were almost 100-fold slower than unmodified mRNAs. In contrast to peptidyl transfer, the modifications had little effect on GTP hydrolysis by elongation factor thermal unstable (EF-Tu), suggesting that only the proofreading phase of tRNA selection depends critically on the kink structure. Although the modifications appear to have no effect on typical cognate interactions, peptidyl transfer for a tRNA that uses atypical base pairing is compromised. These observations suggest that the kink structure is important for decoding in the absence of Watson-Crick or G-U wobble base pairing at the third position. Our findings provide evidence for a previously unappreciated role for the mRNA backbone in ensuring uniform decoding of the genetic code.
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11
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Pierson WE, Hoffer ED, Keedy HE, Simms CL, Dunham CM, Zaher HS. Uniformity of Peptide Release Is Maintained by Methylation of Release Factors. Cell Rep 2017; 17:11-18. [PMID: 27681416 DOI: 10.1016/j.celrep.2016.08.085] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/30/2016] [Accepted: 08/24/2016] [Indexed: 10/20/2022] Open
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.
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Affiliation(s)
- William E Pierson
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Eric D Hoffer
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA; Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA
| | - Hannah E Keedy
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Carrie L Simms
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA.
| | - Hani S Zaher
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA.
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12
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Wang J, Forster AC. Translational roles of the C75 2'OH in an in vitro tRNA transcript at the ribosomal A, P and E sites. Sci Rep 2017; 7:6709. [PMID: 28751745 PMCID: PMC5532260 DOI: 10.1038/s41598-017-06991-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/21/2017] [Indexed: 11/26/2022] Open
Abstract
Aminoacyl-tRNAs containing a deoxy substitution in the penultimate nucleotide (C75 2′OH → 2′H) have been widely used in translation for incorporation of unnatural amino acids (AAs). However, this supposedly innocuous modification surprisingly increased peptidyl-tRNAAlaugc drop off in biochemical assays of successive incorporations. Here we predict the function of this tRNA 2′OH in the ribosomal A, P and E sites using recent co-crystal structures of ribosomes and tRNA substrates and test these structure-function models by systematic kinetics analyses. Unexpectedly, the C75 2′H did not affect A- to P-site translocation nor peptidyl donor activity of tRNAAlaugc. Rather, the peptidyl acceptor activity of the A-site Ala-tRNAAlaugc and the translocation of the P-site deacylated tRNAAlaugc to the E site were impeded. Delivery by EF-Tu was not significantly affected. This broadens our view of the roles of 2′OH groups in tRNAs in translation.
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Affiliation(s)
- Jinfan Wang
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, Uppsala, 75124, Sweden
| | - Anthony C Forster
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, Uppsala, 75124, Sweden.
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13
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Mechanistic Insights Into Catalytic RNA-Protein Complexes Involved in Translation of the Genetic Code. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017. [PMID: 28683922 DOI: 10.1016/bs.apcsb.2017.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
The contemporary world is an "RNA-protein world" rather than a "protein world" and tracing its evolutionary origins is of great interest and importance. The different RNAs that function in close collaboration with proteins are involved in several key physiological processes, including catalysis. Ribosome-the complex megadalton cellular machinery that translates genetic information encoded in nucleotide sequence to amino acid sequence-epitomizes such an association between RNA and protein. RNAs that can catalyze biochemical reactions are known as ribozymes. They usually employ general acid-base catalytic mechanism, often involving the 2'-OH of RNA that activates and/or stabilizes a nucleophile during the reaction pathway. The protein component of such RNA-protein complexes (RNPCs) mostly serves as a scaffold which provides an environment conducive for the RNA to function, or as a mediator for other interacting partners. In this review, we describe those RNPCs that are involved at different stages of protein biosynthesis and in which RNA performs the catalytic function; the focus of the account is on highlighting mechanistic aspects of these complexes. We also provide a perspective on such associations in the context of proofreading during translation of the genetic code. The latter aspect is not much appreciated and recent works suggest that this is an avenue worth exploring, since an understanding of the subject can provide useful insights into how RNAs collaborate with proteins to ensure fidelity during these essential cellular processes. It may also aid in comprehending evolutionary aspects of such associations.
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14
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Theoretical study of a proton wire mechanism for the peptide bond formation in the ribosome. Theor Chem Acc 2017. [DOI: 10.1007/s00214-017-2066-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Lehmann J. Induced fit of the peptidyl-transferase center of the ribosome and conformational freedom of the esterified amino acids. RNA (NEW YORK, N.Y.) 2017; 23:229-239. [PMID: 27879432 PMCID: PMC5238797 DOI: 10.1261/rna.057273.116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 11/18/2016] [Indexed: 06/06/2023]
Abstract
The catalytic site of most enzymes can efficiently handle only one substrate. In contrast, the ribosome is capable of polymerizing at a similar rate at least 20 different kinds of amino acids from aminoacyl-tRNA carriers while using just one catalytic site, the peptidyl-transferase center (PTC). An induced-fit mechanism has been uncovered in the PTC, but a possible connection between this mechanism and the uniform handling of the substrates has not been investigated. We present an analysis of published ribosome structures supporting the hypothesis that the induced fit eliminates unreactive rotamers predominantly populated for some A-site aminoacyl esters before induction. We show that this hypothesis is fully consistent with the wealth of kinetic data obtained with these substrates. Our analysis reveals that induction constrains the amino acids into a reactive conformation in a side-chain independent manner. It allows us to highlight the rationale of the PTC structural organization, which confers to the ribosome the very unusual ability to handle large as well as small substrates.
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Affiliation(s)
- Jean Lehmann
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Campus Paris-Saclay, 91198 Gif-sur-Yvette, France
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16
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Wang J, Kwiatkowski M, Forster AC. Ribosomal Peptide Syntheses from Activated Substrates Reveal Rate Limitation by an Unexpected Step at the Peptidyl Site. J Am Chem Soc 2016; 138:15587-15595. [DOI: 10.1021/jacs.6b06936] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jinfan Wang
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
| | - Marek Kwiatkowski
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
| | - Anthony C. Forster
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
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17
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Arenz S, Bock LV, Graf M, Innis CA, Beckmann R, Grubmüller H, Vaiana AC, Wilson DN. A combined cryo-EM and molecular dynamics approach reveals the mechanism of ErmBL-mediated translation arrest. Nat Commun 2016; 7:12026. [PMID: 27380950 PMCID: PMC4935803 DOI: 10.1038/ncomms12026] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/17/2016] [Indexed: 12/30/2022] Open
Abstract
Nascent polypeptides can induce ribosome stalling, regulating downstream genes. Stalling of ErmBL peptide translation in the presence of the macrolide antibiotic erythromycin leads to resistance in Streptococcus sanguis. To reveal this stalling mechanism we obtained 3.6-Å-resolution cryo-EM structures of ErmBL-stalled ribosomes with erythromycin. The nascent peptide adopts an unusual conformation with the C-terminal Asp10 side chain in a previously unseen rotated position. Together with molecular dynamics simulations, the structures indicate that peptide-bond formation is inhibited by displacement of the peptidyl-tRNA A76 ribose from its canonical position, and by non-productive interactions of the A-tRNA Lys11 side chain with the A-site crevice. These two effects combine to perturb peptide-bond formation by increasing the distance between the attacking Lys11 amine and the Asp10 carbonyl carbon. The interplay between drug, peptide and ribosome uncovered here also provides insight into the fundamental mechanism of peptide-bond formation.
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Affiliation(s)
- Stefan Arenz
- Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
| | - Lars V. Bock
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37079, Germany
| | - Michael Graf
- Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
| | - C. Axel Innis
- Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac 33607, France
- INSERM U1212, Bordeaux 33076, France
- CNRS UMR7377, Bordeaux 33076, France
| | - Roland Beckmann
- Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
- Center for integrated Protein Science Munich, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37079, Germany
| | - Andrea C. Vaiana
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37079, Germany
| | - Daniel N. Wilson
- Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
- Center for integrated Protein Science Munich, University of Munich, Feodor-Lynenstrasse 25, Munich 81377, Germany
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18
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Protein Elongation, Co-translational Folding and Targeting. J Mol Biol 2016; 428:2165-85. [DOI: 10.1016/j.jmb.2016.03.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 11/18/2022]
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19
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Wang J, Kwiatkowski M, Forster AC. Kinetics of tRNAPyl-mediated amber suppression inEscherichia colitranslation reveals unexpected limiting steps and competing reactions. Biotechnol Bioeng 2016; 113:1552-9. [DOI: 10.1002/bit.25917] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/17/2015] [Accepted: 12/21/2015] [Indexed: 12/30/2022]
Affiliation(s)
- Jinfan Wang
- Department of Cell and Molecular Biology; Uppsala University; Husargatan 3, Box 596 Uppsala 75124 Sweden
| | - Marek Kwiatkowski
- Department of Cell and Molecular Biology; Uppsala University; Husargatan 3, Box 596 Uppsala 75124 Sweden
| | - Anthony C. Forster
- Department of Cell and Molecular Biology; Uppsala University; Husargatan 3, Box 596 Uppsala 75124 Sweden
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20
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Nascent peptide assists the ribosome in recognizing chemically distinct small molecules. Nat Chem Biol 2016; 12:153-8. [PMID: 26727240 PMCID: PMC5726394 DOI: 10.1038/nchembio.1998] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/10/2015] [Indexed: 11/26/2022]
Abstract
Regulation of gene expression in response to the changing environment is critical for cell survival. For instance, binding of macrolide antibiotics to the ribosome promote the translation arrest at the leader ORFs ermCL and ermBL necessary for inducing antibiotic resistance genes ermC and ermB. Cladinose-containing macrolides, like erythromycin (ERY), but not ketolides e.g., telithromycin (TEL), arrest translation of ermCL, while either ERY or TEL stall ermBL translation. How the ribosome distinguishes between chemically similar small molecules is unknown. We show that single amino acid changes in the leader peptide switch the specificity of recognition of distinct molecules, triggering gene activation in response to only ERY, only TEL, to both antibiotics, or preventing stalling altogether. Thus, the ribosomal response to chemical signals can be modulated by minute changes in the nascent peptide, suggesting that protein sequences could have been optimized for rendering translation sensitive to environmental cues.
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21
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Maracci C, Wohlgemuth I, Rodnina MV. Activities of the peptidyl transferase center of ribosomes lacking protein L27. RNA (NEW YORK, N.Y.) 2015; 21:2047-2052. [PMID: 26475831 PMCID: PMC4647459 DOI: 10.1261/rna.053330.115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/04/2015] [Indexed: 06/05/2023]
Abstract
The ribosome is the molecular machine responsible for protein synthesis in all living organisms. Its catalytic core, the peptidyl transferase center (PTC), is built of rRNA, although several proteins reach close to the inner rRNA shell. In the Escherichia coli ribosome, the flexible N-terminal tail of the ribosomal protein L27 contacts the A- and P-site tRNA. Based on computer simulations of the PTC and on previous biochemical evidence, the N-terminal α-amino group of L27 was suggested to take part in the peptidyl-transfer reaction. However, the contribution of this group to catalysis has not been tested experimentally. Here we investigate the role of L27 in peptide-bond formation using fast kinetics approaches. We show that the rate of peptide-bond formation at physiological pH, both with aminoacyl-tRNA or with the substrate analog puromycin, is independent of the presence of L27; furthermore, translation of natural mRNAs is only marginally affected in the absence of L27. The pH dependence of the puromycin reaction is unaltered in the absence of L27, indicating that the N-terminal α-amine is not the ionizing group taking part in catalysis. Likewise, L27 is not required for the peptidyl-tRNA hydrolysis during termination. Thus, apart from the known effect on subunit association, which most likely explains the phenotype of the deletion strains, L27 does not appear to be a key player in the core mechanism of peptide-bond formation on the ribosome.
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Affiliation(s)
- Cristina Maracci
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Ingo Wohlgemuth
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
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22
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Wang J, Kwiatkowski M, Forster AC. Kinetics of Ribosome-Catalyzed Polymerization Using Artificial Aminoacyl-tRNA Substrates Clarifies Inefficiencies and Improvements. ACS Chem Biol 2015; 10:2187-92. [PMID: 26191973 DOI: 10.1021/acschembio.5b00335] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribosomal synthesis of polymers of unnatural amino acids (AAs) is limited by low incorporation efficiencies using the artificial AA-tRNAs, but the kinetics have yet to be studied. Here, kinetics were performed on five consecutive incorporations using various artificial AA-tRNAs with all intermediate products being analyzed. Yields within a few seconds displayed similar trends to our prior yields after 30 min without preincubation, demonstrating the relevance of fast kinetics to traditional long-incubation translations. Interestingly, the two anticodon swaps were much less inhibitory in the present optimized system, which should allow more flexibility in the engineering of artificial AA-tRNAs. The biggest kinetic defect was caused by the penultimate dC introduced from the standard, chemoenzymatic, charging method. This prompted peptidyl-tRNA drop-off, decreasing processivities during five consecutive AA incorporations. Indeed, two tRNA charging methods that circumvented the dC dramatically improved efficiencies of ribosomal, consecutive, unnatural AA incorporations to give near wild-type kinetics.
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Affiliation(s)
- Jinfan Wang
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
| | - Marek Kwiatkowski
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
| | - Anthony C. Forster
- Department of Cell and Molecular
Biology, Uppsala University, Husargatan 3, Box
596, Uppsala 75124, Sweden
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23
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Świderek K, Marti S, Tuñón I, Moliner V, Bertran J. Peptide Bond Formation Mechanism Catalyzed by Ribosome. J Am Chem Soc 2015; 137:12024-34. [PMID: 26325003 PMCID: PMC4582011 DOI: 10.1021/jacs.5b05916] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this paper we present a study of the peptide bond formation reaction catalyzed by ribosome. Different mechanistic proposals have been explored by means of Free Energy Perturbation methods within hybrid QM/MM potentials, where the chemical system has been described by the M06-2X functional and the environment by means of the AMBER force field. According to our results, the most favorable mechanism in the ribosome would proceed through an eight-membered ring transition state, involving a proton shuttle mechanism through the hydroxyl group of the sugar and a water molecule. This transition state is similar to that described for the reaction in solution (J. Am. Chem. Soc. 2013, 135, 8708-8719), but the reaction mechanisms are noticeably different. Our simulations reproduce the experimentally determined catalytic effect of ribosome that can be explained by the different behavior of the two environments. While the solvent reorganizes during the chemical process involving an entropic penalty, the ribosome is preorganized in the formation of the Michaelis complex and does not suffer important changes along the reaction, dampening the charge redistribution of the chemical system.
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Affiliation(s)
- Katarzyna Świderek
- Departament de Química Física i Analítica; Universitat Jaume I, 12071 Castellón (Spain)
- Institute of Applied Radiation Chemistry, Lodz University of Technology, 90-924 Lodz, (Poland)
| | - Sergio Marti
- Departament de Química Física i Analítica; Universitat Jaume I, 12071 Castellón (Spain)
| | - Iñaki Tuñón
- Departament de Química Física, Universitat de València, 46100 Burjasot, (Spain)
| | - Vicent Moliner
- Departament de Química Física i Analítica; Universitat Jaume I, 12071 Castellón (Spain)
| | - Juan Bertran
- Departament de Química; Universitat Autònoma de Barcelona, 08193 Bellaterra, (Spain)
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24
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Maini R, Chowdhury SR, Dedkova LM, Roy B, Daskalova SM, Paul R, Chen S, Hecht SM. Protein Synthesis with Ribosomes Selected for the Incorporation of β-Amino Acids. Biochemistry 2015; 54:3694-706. [PMID: 25982410 PMCID: PMC4472090 DOI: 10.1021/acs.biochem.5b00389] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/16/2015] [Indexed: 02/04/2023]
Abstract
In an earlier study, β³-puromycin was used for the selection of modified ribosomes, which were utilized for the incorporation of five different β-amino acids into Escherichia coli dihydrofolate reductase (DHFR). The selected ribosomes were able to incorporate structurally disparate β-amino acids into DHFR, in spite of the use of a single puromycin for the selection of the individual clones. In this study, we examine the extent to which the structure of the β³-puromycin employed for ribosome selection influences the regio- and stereochemical preferences of the modified ribosomes during protein synthesis; the mechanistic probe was a single suppressor tRNA(CUA) activated with each of four methyl-β-alanine isomers (1-4). The modified ribosomes were found to incorporate each of the four isomeric methyl-β-alanines into DHFR but exhibited a preference for incorporation of 3(S)-methyl-β-alanine (β-mAla; 4), i.e., the isomer having the same regio- and stereochemistry as the O-methylated β-tyrosine moiety of β³-puromycin. Also conducted were a selection of clones that are responsive to β²-puromycin and a demonstration of reversal of the regio- and stereochemical preferences of these clones during protein synthesis. These results were incorporated into a structural model of the modified regions of 23S rRNA, which included in silico prediction of a H-bonding network. Finally, it was demonstrated that incorporation of 3(S)-methyl-β-alanine (β-mAla; 4) into a short α-helical region of the nucleic acid binding domain of hnRNP LL significantly stabilized the helix without affecting its DNA binding properties.
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MESH Headings
- Alanine/analogs & derivatives
- Alanine/chemistry
- Alanine/metabolism
- Escherichia coli/enzymology
- Escherichia coli/metabolism
- Escherichia coli Proteins/biosynthesis
- Escherichia coli Proteins/chemistry
- Heterogeneous-Nuclear Ribonucleoprotein L/biosynthesis
- Heterogeneous-Nuclear Ribonucleoprotein L/chemistry
- Heterogeneous-Nuclear Ribonucleoprotein L/genetics
- Humans
- Hydrogen Bonding
- Models, Molecular
- Molecular Dynamics Simulation
- Mutant Proteins/biosynthesis
- Mutant Proteins/chemistry
- Mutant Proteins/genetics
- Nucleotide Motifs
- Peptidyl Transferases/genetics
- Peptidyl Transferases/metabolism
- Protein Conformation
- Protein Stability
- Puromycin/analogs & derivatives
- Puromycin/chemistry
- Puromycin/metabolism
- RNA, Bacterial/chemistry
- RNA, Bacterial/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 23S/chemistry
- RNA, Ribosomal, 23S/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Ribosomes/metabolism
- Stereoisomerism
- Substrate Specificity
- Tetrahydrofolate Dehydrogenase/biosynthesis
- Tetrahydrofolate Dehydrogenase/chemistry
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Affiliation(s)
- Rumit Maini
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Sandipan Roy Chowdhury
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Larisa M. Dedkova
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Basab Roy
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Sasha M. Daskalova
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Rakesh Paul
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Shengxi Chen
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Sidney M. Hecht
- Center for BioEnergetics,
Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
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25
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The ribosome can discriminate the chirality of amino acids within its peptidyl-transferase center. Proc Natl Acad Sci U S A 2015; 112:6038-43. [PMID: 25918365 DOI: 10.1073/pnas.1424712112] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The cellular translational machinery (TM) synthesizes proteins using exclusively L- or achiral aminoacyl-tRNAs (aa-tRNAs), despite the presence of D-amino acids in nature and their ability to be aminoacylated onto tRNAs by aa-tRNA synthetases. The ubiquity of L-amino acids in proteins has led to the hypothesis that D-amino acids are not substrates for the TM. Supporting this view, protein engineering efforts to incorporate D-amino acids into proteins using the TM have thus far been unsuccessful. Nonetheless, a mechanistic understanding of why D-aa-tRNAs are poor substrates for the TM is lacking. To address this deficiency, we have systematically tested the translation activity of D-aa-tRNAs using a series of biochemical assays. We find that the TM can effectively, albeit slowly, accept D-aa-tRNAs into the ribosomal aa-tRNA binding (A) site, use the A-site D-aa-tRNA as a peptidyl-transfer acceptor, and translocate the resulting peptidyl-D-aa-tRNA into the ribosomal peptidyl-tRNA binding (P) site. During the next round of continuous translation, however, we find that ribosomes carrying a P-site peptidyl-D-aa-tRNA partition into subpopulations that are either translationally arrested or that can continue translating. Consistent with its ability to arrest translation, chemical protection experiments and molecular dynamics simulations show that P site-bound peptidyl-D-aa-tRNA can trap the ribosomal peptidyl-transferase center in a conformation in which peptidyl transfer is impaired. Our results reveal a novel mechanism through which D-aa-tRNAs interfere with translation, provide insight into how the TM might be engineered to use D-aa-tRNAs, and increase our understanding of the physiological role of a widely distributed enzyme that clears D-aa-tRNAs from cells.
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26
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Jain S, Richardson DC, Richardson JS. Computational Methods for RNA Structure Validation and Improvement. Methods Enzymol 2015; 558:181-212. [PMID: 26068742 DOI: 10.1016/bs.mie.2015.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
With increasing recognition of the roles RNA molecules and RNA/protein complexes play in an unexpected variety of biological processes, understanding of RNA structure-function relationships is of high current importance. To make clean biological interpretations from three-dimensional structures, it is imperative to have high-quality, accurate RNA crystal structures available, and the community has thoroughly embraced that goal. However, due to the many degrees of freedom inherent in RNA structure (especially for the backbone), it is a significant challenge to succeed in building accurate experimental models for RNA structures. This chapter describes the tools and techniques our research group and our collaborators have developed over the years to help RNA structural biologists both evaluate and achieve better accuracy. Expert analysis of large, high-resolution, quality-conscious RNA datasets provides the fundamental information that enables automated methods for robust and efficient error diagnosis in validating RNA structures at all resolutions. The even more crucial goal of correcting the diagnosed outliers has steadily developed toward highly effective, computationally based techniques. Automation enables solving complex issues in large RNA structures, but cannot circumvent the need for thoughtful examination of local details, and so we also provide some guidance for interpreting and acting on the results of current structure validation for RNA.
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Affiliation(s)
- Swati Jain
- Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina, USA; Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA; Department of Computer Science, Duke University, Durham, North Carolina, USA
| | - David C Richardson
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA.
| | - Jane S Richardson
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
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27
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A theoretical model investigation of peptide bond formation involving two water molecules in ribosome supports the two-step and eight membered ring mechanism. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Bernhardt HS. The Juxtaposition of Ribose Hydroxyl Groups: The Root of Biological Catalysis and the RNA World? ORIGINS LIFE EVOL B 2015; 45:15-9. [DOI: 10.1007/s11084-015-9403-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
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29
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Monajemi H, Mohd Zain S, Wan Abdullah WAT. The P-site A76 2′-OH acts as a peptidyl shuttle in a stepwise peptidyl transfer mechanism. RSC Adv 2015. [DOI: 10.1039/c5ra02767e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The P-site-A76-2′OH transfers the polypeptide chain to the A-site α-amine and A2451 facilitates this transfer by acting as proton shuttle.
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Affiliation(s)
- Hadieh Monajemi
- Department of Physics
- Faculty of Science
- Universiti Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - Sharifuddin Mohd Zain
- Department of Chemistry
- Faculty of Science
- Universiti Malaya
- 50603 Kuala Lumpur
- Malaysia
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30
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A proton wire to couple aminoacyl-tRNA accommodation and peptide-bond formation on the ribosome. Nat Struct Mol Biol 2014; 21:787-93. [PMID: 25132179 PMCID: PMC4156881 DOI: 10.1038/nsmb.2871] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 07/14/2014] [Indexed: 11/12/2022]
Abstract
During peptide bond formation on the ribosome the α-amine of an aminoacyl-tRNA attacks the ester carbonyl carbon of a peptidyl-tRNA to yield a peptide lengthened by one amino acid. Although the ribosome's contribution to catalysis is predominantly entropic, the lack of high-resolution structural data for the complete active site in complex with full-length ligands has made it difficult to assess how the ribosome might influence the pathway of the reaction. Here, we present crystal structures of pre-attack and post-catalysis complexes of the Thermus thermophilus 70S ribosome at ∼2.6 Å resolution. These structures reveal a network of hydrogen bonds along which proton transfer could take place to ensure the concerted, rate-limiting formation of a tetrahedral intermediate. Unlike earlier models, we propose that the ribosome and the A-site tRNA facilitate the deprotonation of the nucleophile through the activation of a water molecule.
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31
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Acosta-Silva C, Bertran J, Branchadell V, Oliva A. Theoretical Study on Two-Step Mechanisms of Peptide Release in the Ribosome. J Phys Chem B 2014; 118:5717-29. [DOI: 10.1021/jp501246a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carles Acosta-Silva
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Joan Bertran
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Vicenç Branchadell
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Antoni Oliva
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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32
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Abstract
The lariat-capping (LC) ribozyme is a natural ribozyme isolated from eukaryotic microorganisms. Despite apparent structural similarity to group I introns, the LC ribozyme catalyzes cleavage by a 2',5' branching reaction, leaving the 3' product with a 3-nt lariat cap that functionally substitutes for a conventional mRNA cap in the downstream pre-mRNA encoding a homing endonuclease. We describe the crystal structures of the precleavage and postcleavage LC ribozymes, which suggest that structural features inherited from group I ribozymes have undergone speciation due to profound changes in molecular selection pressure, ultimately giving rise to an original branching ribozyme family. The structures elucidate the role of key elements that regulate the activity of the LC ribozyme by conformational switching and suggest a mechanism by which the signal for branching is transmitted to the catalytic core. The structures also show how conserved interactions twist residues, forming the lariat to join chemical groups involved in branching.
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33
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Abstract
Post-transcriptional cleavage of RNA molecules to generate smaller fragments is a widespread mechanism that enlarges the structural and functional complexity of cellular RNomes. Substrates for such RNA fragmentations are coding as well as non-protein-coding RNAs. In particular, fragments derived from both precursor and mature tRNAs represent one of the rapidly growing classes of post-transcriptional RNA pieces. Importantly, these tRNA fragments possess distinct expression patterns, abundance, cellular localizations, or biological roles compared with their parental tRNA molecules. Here we review recent reports on tRNA cleavage and attempt to categorize tRNA pieces according to their origin and cellular function. The biological scope of tRNA-derived fragments ranges from translation control, over RNA silencing, to regulating apoptosis, and thus clearly enlarges the functional repertoire of ncRNA biology.
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Affiliation(s)
- Jennifer Gebetsberger
- Department of Chemistry and Biochemistry; University of Bern; Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences; University of Bern; Bern, Switzerland
| | - Norbert Polacek
- Department of Chemistry and Biochemistry; University of Bern; Bern, Switzerland; Division of Genomics and RNomics; Medical University Innsbruck; Innsbruck, Austria
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34
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Rivas M, Tran Q, Fox GE. Nanometer scale pores similar in size to the entrance of the ribosomal exit cavity are a common feature of large RNAs. RNA (NEW YORK, N.Y.) 2013; 19:1349-1354. [PMID: 23940386 PMCID: PMC3854525 DOI: 10.1261/rna.038828.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
The highly conserved peptidyl transferase center (PTC) of the ribosome contains an RNA pore that serves as the entrance to the exit tunnel. Analysis of available ribosome crystal structures has revealed the presence of multiple additional well-defined pores of comparable size in the ribosomal (rRNA) RNAs. These typically have dimensions of 1-2 nm, with a total area of ∼100 Å(2) or more, and most are associated with one or more ribosomal proteins. The PTC example and the other rRNA pores result from the packing of helices. However, in the non-PTC cases the nitrogenous bases do not protrude into the pore, thereby limiting the potential for hydrogen bonding within the pore. Instead, it is the RNA backbone that largely defines the pore likely resulting in a negatively charged environment. In many but not all cases, ribosomal proteins are associated with the pores to a greater or lesser extent. With the exception of the PTC case, the large subunit pores are not found in what are thought to be the evolutionarily oldest regions of the 23S rRNA. The unusual nature of the PTC pore may reflect a history of being created by hybridization between two or more RNAs early in evolution rather than simple folding of a single RNA. An initial survey of nonribosomal RNA crystal structures revealed additional pores, thereby showing that they are likely a general feature of RNA tertiary structure.
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Affiliation(s)
- Mario Rivas
- Laboratorio de Origen de la Vida, Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Coyoacán, C.P. 0451, Mexico
| | - Quyen Tran
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
| | - George E. Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
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35
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Affiliation(s)
| | - V. Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; ,
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36
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Rodnina MV. The ribosome as a versatile catalyst: reactions at the peptidyl transferase center. Curr Opin Struct Biol 2013; 23:595-602. [PMID: 23711800 DOI: 10.1016/j.sbi.2013.04.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 04/10/2013] [Indexed: 11/29/2022]
Abstract
In all contemporary organisms, the active site of the ribosome--the peptidyl transferase center--catalyzes two distinct reactions, peptide bond formation between peptidyl-tRNA and aminoacyl-tRNA as well as the hydrolysis of peptidyl-tRNA with the help of a release factor. However, when provided with appropriate substrates, ribosomes can also catalyze a broad range of other chemical reaction, which provides the basis for orthogonal translation and synthesis of alloproteins from unnatural building blocks. Advances in understanding the mechanisms of the two ubiquitous reactions, the peptide bond formation and peptide release, provide insights into the versatility of the active site of the ribosome. Release factors 1 and 2 and elongation factor P are auxiliary factors that augment the intrinsic catalytic activity of the ribosome in special cases.
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Affiliation(s)
- Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany.
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37
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Acosta-Silva C, Bertran J, Branchadell V, Oliva A. Quantum Mechanical Study on the Mechanism of Peptide Release in the Ribosome. J Phys Chem B 2013; 117:3503-15. [DOI: 10.1021/jp3110248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Carles Acosta-Silva
- Departament de Química, Universitat Autònoma
de Barcelona, 08193 Bellaterra, Spain
| | - Joan Bertran
- Departament de Química, Universitat Autònoma
de Barcelona, 08193 Bellaterra, Spain
| | - Vicenç Branchadell
- Departament de Química, Universitat Autònoma
de Barcelona, 08193 Bellaterra, Spain
| | - Antoni Oliva
- Departament de Química, Universitat Autònoma
de Barcelona, 08193 Bellaterra, Spain
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38
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Shaw JJ, Trobro S, He SL, Åqvist J, Green R. A Role for the 2' OH of peptidyl-tRNA substrate in peptide release on the ribosome revealed through RF-mediated rescue. ACTA ACUST UNITED AC 2012; 19:983-93. [PMID: 22921065 DOI: 10.1016/j.chembiol.2012.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 05/12/2012] [Accepted: 06/01/2012] [Indexed: 11/25/2022]
Abstract
The 2' OH of the peptidyl-tRNA substrate is thought to be important for catalysis of both peptide bond formation and peptide release in the ribosomal active site. The release reaction also specifically depends on a release factor protein (RF) to hydrolyze the ester linkage of the peptidyl-tRNA upon recognition of stop codons in the A site. Here, we demonstrate that certain amino acid substitutions (in particular those containing hydroxyl or thiol groups) in the conserved GGQ glutamine of release factor RF1 can rescue defects in the release reaction associated with peptidyl-tRNA substrates lacking a 2' OH. We explored this rescue effect through biochemical and computational approaches that support a model where the 2' OH of the P-site substrate is critical for orienting the nucleophile in a hydrogen-bonding network productive for catalysis.
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Affiliation(s)
- Jeffrey J Shaw
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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39
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Fukushima K, Iwahashi H, Nishikimi M. ONIOM Study of a Proton Shuttle-Catalyzed Stepwise Mechanism for Peptide Bond Formation in the Ribosome. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
| | | | - Morimitsu Nishikimi
- Department of Food Science and Nutrition, Faculty of Human Life and Environmental Sciences, Nagoya Women’s University
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Aqvist J, Lind C, Sund J, Wallin G. Bridging the gap between ribosome structure and biochemistry by mechanistic computations. Curr Opin Struct Biol 2012; 22:815-23. [PMID: 22884263 DOI: 10.1016/j.sbi.2012.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 06/14/2012] [Accepted: 07/09/2012] [Indexed: 11/18/2022]
Abstract
The wealth of structural and biochemical data now available for protein synthesis on the ribosome presents major new challenges for computational biochemistry. Apart from technical difficulties in modeling ribosome systems, the complexity of the overall translation cycle with a multitude of different kinetic steps presents a formidable problem for computational efforts where we have only seen the beginning. However, a range of methodologies including molecular dynamics simulations, free energy calculations, molecular docking and quantum chemical approaches have already been put to work with promising results. In particular, the combined efforts of structural biology, biochemistry, kinetics and computational modeling can lead towards a quantitative structure-based description of translation.
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Affiliation(s)
- Johan Aqvist
- Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Box 596, SE-751 24 Uppsala, Sweden.
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Acosta-Silva C, Bertran J, Branchadell V, Oliva A. Quantum-Mechanical Study on the Mechanism of Peptide Bond Formation in the Ribosome. J Am Chem Soc 2012; 134:5817-31. [DOI: 10.1021/ja209558d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Carles Acosta-Silva
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Joan Bertran
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Vicenç Branchadell
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Antoni Oliva
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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Kavaliauskas D, Nissen P, Knudsen CR. The busiest of all ribosomal assistants: elongation factor Tu. Biochemistry 2012; 51:2642-51. [PMID: 22409271 DOI: 10.1021/bi300077s] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
During translation, the nucleic acid language employed by genes is translated into the amino acid language used by proteins. The translator is the ribosome, while the dictionary employed is known as the genetic code. The genetic information is presented to the ribosome in the form of a mRNA, and tRNAs connect the two languages. Translation takes place in three steps: initiation, elongation, and termination. After a protein has been synthesized, the components of the translation apparatus are recycled. During each phase of translation, the ribosome collaborates with specific translation factors, which secure a proper balance between speed and fidelity. Notably, initiation, termination, and ribosomal recycling occur only once per protein produced during normal translation, while the elongation step is repeated a large number of times, corresponding to the number of amino acids constituting the protein of interest. In bacteria, elongation factor Tu plays a central role during the selection of the correct amino acids throughout the elongation phase of translation. Elongation factor Tu is the main subject of this review.
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Affiliation(s)
- Darius Kavaliauskas
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
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43
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Abstract
The ability of RNA to both store genetic information and catalyse chemical reactions has led to the hypothesis that it predates DNA and proteins. While there is no doubt that RNA is capable of storing the genetic information of a primitive organism, only two classes of reactions-phosphoryl transfer and peptide bond formation-have been observed to be catalysed by RNA in nature. However, these naturally occurring ribozymes use a wide range of catalytic strategies that could be applied to other reactions. Furthermore, RNA can bind several cofactors that are used by protein enzymes to facilitate a wide variety of chemical processes. Despite its limited functional groups, these observations indicate RNA is a versatile molecule that could, in principle, catalyse the myriad reactions necessary to sustain life.
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Affiliation(s)
- David A Hiller
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
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Pech M, Nierhaus KH. The thorny way to the mechanism of ribosomal peptide-bond formation. Chembiochem 2012; 13:189-92. [PMID: 22213275 DOI: 10.1002/cbic.201100660] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Indexed: 11/08/2022]
Affiliation(s)
- Markus Pech
- Department, AG Ribosomen, Abteilung Vingron, Max-Planck-Insitut für Molekulare Genetik, Ihnestrasse 73, 14195 Berlin, Germany
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Carrasco N, Hiller DA, Strobel SA. Minimal Transition State Charge Stabilization of the Oxyanion during Peptide Bond Formation by the Ribosome. Biochemistry 2011; 50:10491-8. [DOI: 10.1021/bi201290s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Nicolas Carrasco
- Departments of Molecular Biophysics & Biochemistry and Chemistry, Yale University, 260 Whitney Ave., New Haven, Connecticut 06520-81114, United States
| | - David A. Hiller
- Departments of Molecular Biophysics & Biochemistry and Chemistry, Yale University, 260 Whitney Ave., New Haven, Connecticut 06520-81114, United States
| | - Scott A. Strobel
- Departments of Molecular Biophysics & Biochemistry and Chemistry, Yale University, 260 Whitney Ave., New Haven, Connecticut 06520-81114, United States
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Korostelev AA. Structural aspects of translation termination on the ribosome. RNA (NEW YORK, N.Y.) 2011; 17:1409-1421. [PMID: 21700725 PMCID: PMC3153966 DOI: 10.1261/rna.2733411] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Translation of genetic information encoded in messenger RNAs into polypeptide sequences is carried out by ribosomes in all organisms. When a full protein is synthesized, a stop codon positioned in the ribosomal A site signals termination of translation and protein release. Translation termination depends on class I release factors. Recently, atomic-resolution crystal structures were determined for bacterial 70S ribosome termination complexes bound with release factors RF1 or RF2. In combination with recent biochemical studies, the structures resolve long-standing questions about translation termination. They bring insights into the mechanisms of recognition of all three stop codons, peptidyl-tRNA hydrolysis, and coordination of stop-codon recognition with peptidyl-tRNA hydrolysis. In this review, the structural aspects of these mechanisms are discussed.
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Affiliation(s)
- Andrei A Korostelev
- RNA Therapeutics Institute and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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A two-step chemical mechanism for ribosome-catalysed peptide bond formation. Nature 2011; 476:236-9. [PMID: 21765427 PMCID: PMC3154986 DOI: 10.1038/nature10248] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/03/2011] [Indexed: 01/18/2023]
Abstract
The chemical step of natural protein synthesis, peptide bond formation, is catalysed by the large subunit of the ribosome. Crystal structures have shown that the active site for peptide bond formation is composed entirely of RNA. Recent work has focused on how an RNA active site is able to catalyse this fundamental biological reaction at a suitable rate for protein synthesis. On the basis of the absence of important ribosomal functional groups, lack of a dependence on pH, and the dominant contribution of entropy to catalysis, it has been suggested that the role of the ribosome is limited to bringing the substrates into close proximity. Alternatively, the importance of the 2'-hydroxyl of the peptidyl-transfer RNA and a Brønsted coefficient near zero have been taken as evidence that the ribosome coordinates a proton-transfer network. Here we report the transition state of peptide bond formation, based on analysis of the kinetic isotope effect at five positions within the reaction centre of a peptidyl-transfer RNA mimic. Our results indicate that in contrast to the uncatalysed reaction, formation of the tetrahedral intermediate and proton transfer from the nucleophilic nitrogen both occur in the rate-limiting step. Unlike in previous proposals, the reaction is not fully concerted; instead, breakdown of the tetrahedral intermediate occurs in a separate fast step. This suggests that in addition to substrate positioning, the ribosome is contributing to chemical catalysis by changing the rate-limiting transition state.
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