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Nikonov OS, Nikonova EY, Tarabarova AG, Mikhaylina AO, Kravchenko OV, Nevskaya NA, Nikonov SV. Recognition of γ-Subunit by β-Subunit in Translation Initiation Factor 2. Stabilization of the GTP-Bound State of I/F 2 in Archaea and Eukaryotes. BIOCHEMISTRY (MOSCOW) 2023; 88:221-230. [PMID: 37072332 DOI: 10.1134/s0006297923020062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Eukaryotic and archaeal translation initiation factor 2 (e/aIF2) functions as a heterotrimeric complex. It consists of three subunits (α, β, γ). α- and β-subunits are bound to γ-subunit by hydrogen bonds and van der Waals interactions, but do not contact each other. Although main functions of the factor are performed by the γ-subunit, reliable formation of αγ and βγ complexes is necessary for its proper functioning. In this work, we introduced mutations in the recognition part of the βγ interface and showed that hydrophobic effect plays a crucial role in the recognition of subunits both in eukaryotes and archaea. Shape and properties of the groove on the surface of γ-subunit facilitates transition of the disordered recognition part of the β-subunit into an α-helix containing approximately the same number of residues in archaea and eukaryotes. In addition, based on the newly obtained data, it was concluded that in archaea and eukaryotes, transition of the γ-subunit to the active state leads to additional contact between the region of switch 1 and C-terminal part of the β-subunit, which stabilizes helical conformation of the switch.
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Affiliation(s)
- Oleg S Nikonov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Ekaterina Yu Nikonova
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Anastasiia G Tarabarova
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Alisa O Mikhaylina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Olesya V Kravchenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Natalia A Nevskaya
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Stanislav V Nikonov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Nikonov OS, Kravchenko OV, Nevskaya NA, Stolboushkina EA, Garber MB, Nikonov SV. Effect of the Ile222Thr Missense Mutation in SsoIF2γ on the Affinity of γ and β Subunits of aIF2. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521050151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tishchenko SV, Mikhailina AO, Lekontseva NV, Stolboushkina EA, Nikonova EY, Nikonov OS, Nikulin AD. Structural Investigations of RNA–Protein Complexes in Post-Ribosomal Era. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521050217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
Structural studies of RNA–protein complexes are important for understanding many molecular mechanisms occurring in cells (e.g., regulation of protein synthesis and RNA-chaperone activity of proteins). Various objects investigated at the Institute of Protein Research of the Russian Academy of Sciences are considered. Based on the analysis of the structures of the complexes of the ribosomal protein L1 with specific regions on both mRNA and rRNA, the principles of regulation of the translation of the mRNA of its own operon are presented. The studies of the heterotrimeric translation initiation factor IF2 of archaea and eukaryotes are described, and the data on the interaction of glycyl-tRNA-synthetase with viral IRES are reported. The results of studying the interaction of RNA molecules with one of functionally important sites of the Hfq protein are presented, and the differences in the RNA-binding properties of the Hfq and archaeal Lsm proteins are revealed.
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Nikonov OS, Nevskaya NA, Garber MB, Nikonov SV. Structure and Function of Archaeal Translation Initiation Factor 2 Fragments Containing Cys2-Cys2 Motifs. BIOCHEMISTRY (MOSCOW) 2021; 86:1003-1011. [PMID: 34488576 DOI: 10.1134/s0006297921080101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The heterotrimeric (αβγ) translation initiation factor 2 of archaea and eukaryotes (a/eIF2) supplies the P-site of the ribosome with the initiation tRNA. Its two subunits (β and γ) contain the Cys2-Cys2 motif, which is capable of forming a stable zinc finger structure in the presence of zinc ions. In this work, comparative analysis of the fragments containing Cys2-Cys2 motifs in the aIF2β and aIF2γ structures from different organisms was carried out and their environments in crystals was analyzed. Based on the obtained data, a conclusion was made that the conformation and role of these fragments in the β- and γ-subunits of the aIF2 are different.
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Affiliation(s)
- Oleg S Nikonov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Natalia A Nevskaya
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Maria B Garber
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Stanislav V Nikonov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Gordiyenko Y, Llácer JL, Ramakrishnan V. Structural basis for the inhibition of translation through eIF2α phosphorylation. Nat Commun 2019; 10:2640. [PMID: 31201334 PMCID: PMC6572841 DOI: 10.1038/s41467-019-10606-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/10/2019] [Indexed: 11/29/2022] Open
Abstract
One of the responses to stress by eukaryotic cells is the down-regulation of protein synthesis by phosphorylation of translation initiation factor eIF2. Phosphorylation results in low availability of the eIF2 ternary complex (eIF2-GTP-tRNAi) by affecting the interaction of eIF2 with its GTP-GDP exchange factor eIF2B. We have determined the cryo-EM structure of yeast eIF2B in complex with phosphorylated eIF2 at an overall resolution of 4.2 Å. Two eIF2 molecules bind opposite sides of an eIF2B hetero-decamer through eIF2α-D1, which contains the phosphorylated Ser51. eIF2α-D1 is mainly inserted between the N-terminal helix bundle domains of δ and α subunits of eIF2B. Phosphorylation of Ser51 enhances binding to eIF2B through direct interactions of phosphate groups with residues in eIF2Bα and indirectly by inducing contacts of eIF2α helix 58–63 with eIF2Bδ leading to a competition with Met-tRNAi. During stress, protein synthesis is inhibited through phosphorylation of the initiation factor eIF2 on its alpha subunit and its interaction with eIF2B. Here the authors describe a structure of the yeast eIF2B in complex with its substrate - the GDP-bound phosphorylated eIF2, providing insights into how phosphorylation results in a tighter interaction with eIF2B.
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Affiliation(s)
- Yuliya Gordiyenko
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - José Luis Llácer
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK. .,Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas and CIBERER-ISCIII, Valencia, 46010, Spain.
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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Nikonov O, Kravchenko O, Nevskaya N, Stolboushkina E, Garber M, Nikonov S. The third structural switch in the archaeal translation initiation factor 2 (aIF2) molecule and its possible role in the initiation of GTP hydrolysis and the removal of aIF2 from the ribosome. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:392-399. [PMID: 30988256 DOI: 10.1107/s2059798319002304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/12/2019] [Indexed: 11/10/2022]
Abstract
The structure of the γ subunit of archaeal translation initiation factor 2 (aIF2) from Sulfolobus solfataricus (SsoIF2γ) was determined in complex with GDPCP (a GTP analog). Crystals were obtained in the absence of magnesium ions in the crystallization solution. They belonged to space group P1, with five molecules in the unit cell. Four of these molecules are related in pairs by a common noncrystallographic twofold symmetry axis, while the fifth has no symmetry equivalent. Analysis of the structure and its comparison with other known aIF2 γ-subunit structures in the GTP-bound state show that (i) the magnesium ion is necessary for the formation and the maintenance of the active form of SsoIF2γ and (ii) in addition to the two previously known structural switches 1 and 2, eukaryotic translation initiation factor 2 (eIF2) and aIF2 molecules have another flexible region (switch 3), the function of which may consist of initiation of the hydrolysis of GTP and the removal of e/aIF2 from the ribosome after codon-anticodon recognition.
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Affiliation(s)
- Oleg Nikonov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
| | - Olesya Kravchenko
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
| | - Natalia Nevskaya
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
| | - Elena Stolboushkina
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
| | - Maria Garber
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
| | - Stanislav Nikonov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russian Federation
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Start Codon Recognition in Eukaryotic and Archaeal Translation Initiation: A Common Structural Core. Int J Mol Sci 2019; 20:ijms20040939. [PMID: 30795538 PMCID: PMC6412873 DOI: 10.3390/ijms20040939] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 01/12/2023] Open
Abstract
Understanding molecular mechanisms of ribosomal translation sheds light on the emergence and evolution of protein synthesis in the three domains of life. Universally, ribosomal translation is described in three steps: initiation, elongation and termination. During initiation, a macromolecular complex assembled around the small ribosomal subunit selects the start codon on the mRNA and defines the open reading frame. In this review, we focus on the comparison of start codon selection mechanisms in eukaryotes and archaea. Eukaryotic translation initiation is a very complicated process, involving many initiation factors. The most widespread mechanism for the discovery of the start codon is the scanning of the mRNA by a pre-initiation complex until the first AUG codon in a correct context is found. In archaea, long-range scanning does not occur because of the presence of Shine-Dalgarno (SD) sequences or of short 5′ untranslated regions. However, archaeal and eukaryotic translation initiations have three initiation factors in common: e/aIF1, e/aIF1A and e/aIF2 are directly involved in the selection of the start codon. Therefore, the idea that these archaeal and eukaryotic factors fulfill similar functions within a common structural ribosomal core complex has emerged. A divergence between eukaryotic and archaeal factors allowed for the adaptation to the long-range scanning process versus the SD mediated prepositioning of the ribosome.
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Kravchenko OV, Nikonov OS, Nevskaya NA, Stolboushkina EA, Arkhipova VI, Garber MB, Nikonov SV. Perfect Hemihedral Twinning in Crystals of the γ-Subunit of Translation Initiation Factor 2 from Sulfolobus solfataricus: Cause and Effect. BIOCHEMISTRY (MOSCOW) 2016; 81:1205-1212. [PMID: 27908245 DOI: 10.1134/s0006297916100187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The crystal structure of the γ-subunit of translation initiation factor 2 from the archaeon Sulfolobus solfataricus (SsoIF2γ) has been solved based on perfectly hemihedral twinned data. The protein was cocrystallized with the 10-fold molar excess of GTP analog (GDPCP) over protein. However, no nucleotide was found in the structure, and the model demonstrated the apo form of the protein. Two slightly different molecules in the asymmetric unit of the crystal are related by the non-crystallographic 2-fold axis and form a tightly associated dimer. This dimer is stabilized by an intermolecular hydrophobic core and hydrogen bonds. Lack of GDPCP in the nucleotide-binding pocket of the γ-subunit and significant excess of dimers over monomers in the crystallization solution suggest that these dimers are the building blocks of the crystal. Contrary to SsoIF2γ monomers, these dimers are able to crystallize in two oppositely oriented slightly different crystal domains, thus forming a twinned crystal. Comparison of crystallization conditions for the twinned and untwinned crystals of apo SsoIF2γ showed that stabilization of the dimers in the solution may be caused by higher sodium salt concentration. Since amino acid residues involved in intermolecular contacts in the dimer are responsible for binding of the γ- and α-subunits within SsoIF2, increase in sodium salt concentration may prevent functioning of SsoIF2 in the cell.
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Affiliation(s)
- O V Kravchenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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Arkhipova V, Stolboushkina E, Kravchenko O, Kljashtorny V, Gabdulkhakov A, Garber M, Nikonov S, Märtens B, Bläsi U, Nikonov O. Binding of the 5'-Triphosphate End of mRNA to the γ-Subunit of Translation Initiation Factor 2 of the Crenarchaeon Sulfolobus solfataricus. J Mol Biol 2015; 427:3086-95. [PMID: 26244522 DOI: 10.1016/j.jmb.2015.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/30/2015] [Accepted: 07/27/2015] [Indexed: 11/24/2022]
Abstract
The heterotrimeric archaeal IF2 orthologue of eukaryotic translation initiation factor 2 consists of the α-subunit, β-subunit and γ-subunit. Previous studies showed that the γ-subunit of aIF2, besides its central role in Met-tRNAi binding, has an additional function: it binds to the 5'-triphosphorylated end of mRNA and protects its 5'-part from degradation. Competition studies with nucleotides and mRNA, as well as structural and kinetic analyses of aIF2γ mutants, strongly implicate the canonical GTP/GDP-binding pocket in binding to the 5'-triphosphate end of mRNAs. The biological implication of these findings is being discussed.
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Affiliation(s)
- Valentina Arkhipova
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Elena Stolboushkina
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Olesya Kravchenko
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Vladislav Kljashtorny
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Azat Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Maria Garber
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Stanislav Nikonov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation
| | - Birgit Märtens
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna Biocenter, Dr. Bohrgasse 9/4, A-1030 Vienna, Austria
| | - Udo Bläsi
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna Biocenter, Dr. Bohrgasse 9/4, A-1030 Vienna, Austria
| | - Oleg Nikonov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russian Federation.
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Dubiez E, Aleksandrov A, Lazennec-Schurdevin C, Mechulam Y, Schmitt E. Identification of a second GTP-bound magnesium ion in archaeal initiation factor 2. Nucleic Acids Res 2015; 43:2946-57. [PMID: 25690901 PMCID: PMC4357699 DOI: 10.1093/nar/gkv053] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Eukaryotic and archaeal translation initiation processes involve a heterotrimeric GTPase e/aIF2 crucial for accuracy of start codon selection. In eukaryotes, the GTPase activity of eIF2 is assisted by a GTPase-activating protein (GAP), eIF5. In archaea, orthologs of eIF5 are not found and aIF2 GTPase activity is thought to be non-assisted. However, no in vitro GTPase activity of the archaeal factor has been reported to date. Here, we show that aIF2 significantly hydrolyses GTP in vitro. Within aIF2γ, H97, corresponding to the catalytic histidine found in other translational GTPases, and D19, from the GKT loop, both participate in this activity. Several high-resolution crystal structures were determined to get insight into GTP hydrolysis by aIF2γ. In particular, a crystal structure of the H97A mutant was obtained in the presence of non-hydrolyzed GTP. This structure reveals the presence of a second magnesium ion bound to GTP and D19. Quantum chemical/molecular mechanical simulations support the idea that the second magnesium ion may assist GTP hydrolysis by helping to neutralize the developing negative charge in the transition state. These results are discussed in light of the absence of an identified GAP in archaea to assist GTP hydrolysis on aIF2.
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Affiliation(s)
- Etienne Dubiez
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, Ecole Polytechnique, Centre National de la Recherche Scientifique, F-91128 Palaiseau cedex, France
| | - Alexey Aleksandrov
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, Ecole Polytechnique, Centre National de la Recherche Scientifique, F-91128 Palaiseau cedex, France
| | - Christine Lazennec-Schurdevin
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, Ecole Polytechnique, Centre National de la Recherche Scientifique, F-91128 Palaiseau cedex, France
| | - Yves Mechulam
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, Ecole Polytechnique, Centre National de la Recherche Scientifique, F-91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654, Ecole Polytechnique, Centre National de la Recherche Scientifique, F-91128 Palaiseau cedex, France
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