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Dutta S, Nandi N. Dynamics of the Active Sites of Dimeric Seryl tRNA Synthetase from Methanopyrus kandleri. J Phys Chem B 2015; 119:10832-48. [PMID: 25794108 DOI: 10.1021/jp511585w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Saheb Dutta
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Nilashis Nandi
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
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2
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Highlights on trypanosomatid aminoacyl-tRNA synthesis. Subcell Biochem 2013; 74:271-304. [PMID: 24264250 DOI: 10.1007/978-94-007-7305-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Aminoacyl-tRNA synthetases aaRSs are responsible for the aminoacylation of tRNAs in the first step of protein synthesis. They comprise a group of enzymes that catalyze the formation of each possible aminoacyl-tRNA necessary for messenger RNA decoding in a cell. These enzymes have been divided into two classes according to structural features of their active sites and, although each class shares a common active site core, they present an assorted array of appended domains that makes them sufficiently diverse among the different living organisms. Here we will explore what is known about the diversity encountered among trypanosomatids' aaRSs that has helped us not only to understand better the biology of these parasites but can be used rationally for the design of drugs against these protozoa.
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3
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Rokov-Plavec J, Lesjak S, Gruic-Sovulj I, Mocibob M, Dulic M, Weygand-Durasevic I. Substrate recognition and fidelity of maize seryl-tRNA synthetases. Arch Biochem Biophys 2013; 529:122-30. [DOI: 10.1016/j.abb.2012.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 12/27/2022]
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4
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5
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Guitart T, Leon Bernardo T, Sagalés J, Stratmann T, Bernués J, Ribas de Pouplana L. New aminoacyl-tRNA synthetase-like protein in insecta with an essential mitochondrial function. J Biol Chem 2010; 285:38157-66. [PMID: 20870726 PMCID: PMC2992249 DOI: 10.1074/jbc.m110.167486] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 09/22/2010] [Indexed: 12/24/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARS) are modular enzymes that aminoacylate transfer RNAs (tRNA) for their use by the ribosome during protein synthesis. ARS are essential and universal components of the genetic code that were almost completely established before the appearance of the last common ancestor of all living species. This long evolutionary history explains the growing number of functions being discovered for ARS, and for ARS homologues, beyond their canonical role in gene translation. Here we present a previously uncharacterized paralogue of seryl-tRNA synthetase named SLIMP (seryl-tRNA synthetase-like insect mitochondrial protein). SLIMP is the result of a duplication of a mitochondrial seryl-tRNA synthetase (SRS) gene that took place in early metazoans and was fixed in Insecta. Here we show that SLIMP is localized in the mitochondria, where it carries out an essential function that is unrelated to the aminoacylation of tRNA. The knockdown of SLIMP by RNA interference (RNAi) causes a decrease in respiration capacity and an increase in mitochondrial mass in the form of aberrant mitochondria.
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Affiliation(s)
- Tanit Guitart
- From the Institute for Research in Biomedicine (IRB), C/ Baldiri Reixac 12, 08028 Barcelona, Catalonia
| | - Teresa Leon Bernardo
- From the Institute for Research in Biomedicine (IRB), C/ Baldiri Reixac 12, 08028 Barcelona, Catalonia
| | - Jessica Sagalés
- From the Institute for Research in Biomedicine (IRB), C/ Baldiri Reixac 12, 08028 Barcelona, Catalonia
| | - Thomas Stratmann
- the Department of Physiology, University of Barcelona (Biology), Avinguda Diagonal 645, 08028 Barcelona, Catalonia
| | - Jordi Bernués
- From the Institute for Research in Biomedicine (IRB), C/ Baldiri Reixac 12, 08028 Barcelona, Catalonia
- the Institut de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Parc Cientific de Barcelona, Carrer Baldiri Reixac 12, 08028 Barcelona, Catalonia, and
| | - Lluís Ribas de Pouplana
- From the Institute for Research in Biomedicine (IRB), C/ Baldiri Reixac 12, 08028 Barcelona, Catalonia
- the Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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6
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Structure of a tRNA-dependent kinase essential for selenocysteine decoding. Proc Natl Acad Sci U S A 2009; 106:16215-20. [PMID: 19805283 DOI: 10.1073/pnas.0908861106] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Compared to bacteria, archaea and eukaryotes employ an additional enzyme for the biosynthesis of selenocysteine (Sec), the 21(st) natural amino acid (aa). An essential RNA-dependent kinase, O-phosphoseryl-tRNA(Sec) kinase (PSTK), converts seryl-tRNA(Sec) to O-phosphoseryl-tRNA(Sec), the immediate precursor of selenocysteinyl-tRNA(Sec). The sequence of Methanocaldococcus jannaschii PSTK (MjPSTK) suggests an N-terminal kinase domain (177 aa) followed by a presumed tRNA binding region (75 aa). The structures of MjPSTK complexed with ADP and AMPPNP revealed that this enzyme belongs to the P-loop kinase class, and that the kinase domain is closely related to gluconate kinase and adenylate kinase. ATP is bound by the P-loop domain (residues 11-18). Formed by antiparallel dimerization of two PSTK monomers, the enzyme structure shows a deep groove with positive electrostatic potential. Located in this groove is the enzyme's active site, which biochemical and genetic data suggest is composed of Asp-41, Arg-44, Glu-55, Tyr-82, Tyr-83, Met-86, and Met-132. Based on structural comparison with Escherichia coli adenylate kinase a docking model was generated that assigns these amino acids to the recognition of the terminal A76-Ser moieties of Ser-tRNA(Sec). The geometry and electrostatic environment of the groove in MjPSTK are perfectly complementary to the unusually long acceptor helix of tRNA(Sec).
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7
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Jaric J, Bilokapic S, Lesjak S, Crnkovic A, Ban N, Weygand-Durasevic I. Identification of amino acids in the N-terminal domain of atypical methanogenic-type Seryl-tRNA synthetase critical for tRNA recognition. J Biol Chem 2009; 284:30643-51. [PMID: 19734148 DOI: 10.1074/jbc.m109.044099] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Seryl-tRNA synthetase (SerRS) from methanogenic archaeon Methanosarcina barkeri, contains an idiosyncratic N-terminal domain, composed of an antiparallel beta-sheet capped by a helical bundle, connected to the catalytic core by a short linker peptide. It is very different from the coiled-coil tRNA binding domain in bacterial-type SerRS. Because the crystal structure of the methanogenic-type SerRSxtRNA complex has not been obtained, a docking model was produced, which indicated that highly conserved helices H2 and H3 of the N-terminal domain may be important for recognition of the extra arm of tRNA(Ser). Based on structural information and the docking model, we have mutated various positions within the N-terminal region and probed their involvement in tRNA binding and serylation. Total loss of activity and inability of the R76A variant to form the complex with cognate tRNA identifies Arg(76) located in helix H2 as a crucial tRNA-interacting residue. Alteration of Lys(79) positioned in helix H2 and Arg(94) in the loop between helix H2 and beta-strand A4 have a pronounced effect on SerRSxtRNA(Ser) complex formation and dissociation constants (K(D)) determined by surface plasmon resonance. The replacement of residues Arg(38) (located in the loop between helix H1 and beta-strand A2), Lys(141) and Asn(142) (from H3), and Arg(143) (between H3 and H4) moderately affect both the serylation activity and the K(D) values. Furthermore, we have obtained a striking correlation between these results and in vivo effects of these mutations by quantifying the efficiency of suppression of bacterial amber mutations, after coexpression of the genes for M. barkeri suppressor tRNA(Ser) and a set of mMbSerRS variants in Escherichia coli.
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Affiliation(s)
- Jelena Jaric
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
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8
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Sun FJ, Caetano-Anollés G. Evolutionary patterns in the sequence and structure of transfer RNA: a window into early translation and the genetic code. PLoS One 2008; 3:e2799. [PMID: 18665254 PMCID: PMC2474678 DOI: 10.1371/journal.pone.0002799] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 07/02/2008] [Indexed: 01/06/2023] Open
Abstract
Transfer RNA (tRNA) molecules play vital roles during protein synthesis. Their acceptor arms are aminoacylated with specific amino acid residues while their anticodons delimit codon specificity. The history of these two functions has been generally linked in evolutionary studies of the genetic code. However, these functions could have been differentially recruited as evolutionary signatures were left embedded in tRNA molecules. Here we built phylogenies derived from the sequence and structure of tRNA, we forced taxa into monophyletic groups using constraint analyses, tested competing evolutionary hypotheses, and generated timelines of amino acid charging and codon discovery. Charging of Sec, Tyr, Ser and Leu appeared ancient, while specificities related to Asn, Met, and Arg were derived. The timelines also uncovered an early role of the second and then first codon bases, identified codons for Ala and Pro as the most ancient, and revealed important evolutionary take-overs related to the loss of the long variable arm in tRNA. The lack of correlation between ancestries of amino acid charging and encoding indicated that the separate discoveries of these functions reflected independent histories of recruitment. These histories were probably curbed by co-options and important take-overs during early diversification of the living world.
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Affiliation(s)
- Feng-Jie Sun
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Gustavo Caetano-Anollés
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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9
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Abstract
The accurate formation of cognate aminoacyl-transfer RNAs (aa-tRNAs) is essential for the fidelity of translation. Most amino acids are esterified onto their cognate tRNA isoacceptors directly by aa-tRNA synthetases. However, in the case of four amino acids (Gln, Asn, Cys and Sec), aminoacyl-tRNAs are made through indirect pathways in many organisms across all three domains of life. The process begins with the charging of noncognate amino acids to tRNAs by a specialized synthetase in the case of Cys-tRNA(Cys) formation or by synthetases with relaxed specificity, such as the non-discriminating glutamyl-tRNA, non-discriminating aspartyl-tRNA and seryl-tRNA synthetases. The resulting misacylated tRNAs are then converted to cognate pairs through transformation of the amino acids on the tRNA, which is catalyzed by a group of tRNA-dependent modifying enzymes, such as tRNA-dependent amidotransferases, Sep-tRNA:Cys-tRNA synthase, O-phosphoseryl-tRNA kinase and Sep-tRNA:Sec-tRNA synthase. The majority of these indirect pathways are widely spread in all domains of life and thought to be part of the evolutionary process.
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Affiliation(s)
- Jing Yuan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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10
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Bilokapic S, Rokov Plavec J, Ban N, Weygand-Durasevic I. Structural flexibility of the methanogenic-type seryl-tRNA synthetase active site and its implication for specific substrate recognition. FEBS J 2008; 275:2831-44. [DOI: 10.1111/j.1742-4658.2008.06423.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Lesjak S, Weygand-Durasevic I. Recognition between tRNASer and archaeal seryl-tRNA synthetases monitored by suppression of bacterial amber mutations. FEMS Microbiol Lett 2008; 294:111-8. [PMID: 19309487 DOI: 10.1111/j.1574-6968.2009.01560.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Two dissimilar seryl-tRNA synthetases (SerRSs) exist in Methanosarcina barkeri: one of bacterial type (bMbSerRS) and the other resembling SerRSs present only in methanogenic archaea (mMbSerRS). While the expression of the archaeal bMbSerRS gene in Escherichia coli complements the function of thermolabile SerRS at a nonpermissive temperature, mMbSerRS does not. Our recent X-ray structural analysis of mMbSerRS revealed an idiosyncratic N-terminal domain and a catalytic zinc ion in the active site, identifying methanogenic-type SerRSs as atypical members of the SerRS family. To shed further light on substrate discrimination by methanogenic-type SerRS, we developed an in vivo system in E. coli to study tRNA serylation by mMbSerRS variants. We show that coexpression of the M. barkeri SerRS gene, encoding either bacterial- or methanogenic-type SerRS, with the gene for cognate archaeal suppressor tRNA leads to suppression of bacterial amber mutations, implying that the E. coli translation machinery can use serylated tRNA from methanogenic archaea as a substrate in protein synthesis. Furthermore, because serylation of M. barkeri serine-specific tRNA by endogenous E. coli SerRS is negligible, suppression is entirely dependent on recognition between archaeal partners (mMbSerRS/suppressor tRNA(Ser)). Thus, the efficiency of suppression by mMbSerRS variants quantified in the described beta-galactosidase-based reporter system, accurately reflects enzymes' serylation propensity obtained by in vitro kinetic measurements.
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Affiliation(s)
- Sonja Lesjak
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
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12
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Sherrer RL, Ho JML, Söll D. Divergence of selenocysteine tRNA recognition by archaeal and eukaryotic O-phosphoseryl-tRNASec kinase. Nucleic Acids Res 2008; 36:1871-80. [PMID: 18267971 PMCID: PMC2330242 DOI: 10.1093/nar/gkn036] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Selenocysteine (Sec) biosynthesis in archaea and eukaryotes requires three steps: serylation of tRNASec by seryl-tRNA synthetase (SerRS), phosphorylation of Ser-tRNASec by O-phosphoseryl-tRNASec kinase (PSTK), and conversion of O-phosphoseryl-tRNASec (Sep-tRNASec) by Sep-tRNA:Sec-tRNA synthase (SepSecS) to Sec-tRNASec. Although SerRS recognizes both tRNASec and tRNASer species, PSTK must discriminate Ser-tRNASec from Ser-tRNASer. Based on a comparison of the sequences and secondary structures of archaeal tRNASec and tRNASer, we introduced mutations into Methanococcus maripaludis tRNASec to investigate how Methanocaldococcus jannaschii PSTK distinguishes tRNASec from tRNASer. Unlike eukaryotic PSTK, the archaeal enzyme was found to recognize the acceptor stem rather than the length and secondary structure of the D-stem. While the D-arm and T-loop provide minor identity elements, the acceptor stem base pairs G2-C71 and C3-G70 in tRNASec were crucial for discrimination from tRNASer. Furthermore, the A5-U68 base pair in tRNASer has some antideterminant properties for PSTK. Transplantation of these identity elements into the tRNASerUGA scaffold resulted in phosphorylation of the chimeric Ser-tRNA. The chimera was able to stimulate the ATPase activity of PSTK albeit at a lower level than tRNASec, whereas tRNASer did not. Additionally, the seryl moiety of Ser-tRNASec is not required for enzyme recognition, as PSTK efficiently phosphorylated Thr-tRNASec.
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Affiliation(s)
- R Lynn Sherrer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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Sheppard K, Yuan J, Hohn MJ, Jester B, Devine KM, Söll D. From one amino acid to another: tRNA-dependent amino acid biosynthesis. Nucleic Acids Res 2008; 36:1813-25. [PMID: 18252769 PMCID: PMC2330236 DOI: 10.1093/nar/gkn015] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Aminoacyl-tRNAs (aa-tRNAs) are the essential substrates for translation. Most aa-tRNAs are formed by direct aminoacylation of tRNA catalyzed by aminoacyl-tRNA synthetases. However, a smaller number of aa-tRNAs (Asn-tRNA, Gln-tRNA, Cys-tRNA and Sec-tRNA) are made by synthesizing the amino acid on the tRNA by first attaching a non-cognate amino acid to the tRNA, which is then converted to the cognate one catalyzed by tRNA-dependent modifying enzymes. Asn-tRNA or Gln-tRNA formation in most prokaryotes requires amidation of Asp-tRNA or Glu-tRNA by amidotransferases that couple an amidase or an asparaginase to liberate ammonia with a tRNA-dependent kinase. Both archaeal and eukaryotic Sec-tRNA biosynthesis and Cys-tRNA synthesis in methanogens require O-phosophoseryl-tRNA formation. For tRNA-dependent Cys biosynthesis, O-phosphoseryl-tRNA synthetase directly attaches the amino acid to the tRNA which is then converted to Cys by Sep-tRNA: Cys-tRNA synthase. In Sec-tRNA synthesis, O-phosphoseryl-tRNA kinase phosphorylates Ser-tRNA to form the intermediate which is then modified to Sec-tRNA by Sep-tRNA:Sec-tRNA synthase. Complex formation between enzymes in the same pathway may protect the fidelity of protein synthesis. How these tRNA-dependent amino acid biosynthetic routes are integrated into overall metabolism may explain why they are still retained in so many organisms.
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Affiliation(s)
- Kelly Sheppard
- Department of Molecular Biophysics, Yale University, New Haven, CT 06520-8114, USA
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14
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Sherrer RL, O'Donoghue P, Söll D. Characterization and evolutionary history of an archaeal kinase involved in selenocysteinyl-tRNA formation. Nucleic Acids Res 2008; 36:1247-59. [PMID: 18174226 PMCID: PMC2275090 DOI: 10.1093/nar/gkm1134] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Selenocysteine (Sec)-decoding archaea and eukaryotes employ a unique route of Sec-tRNASec synthesis in which O-phosphoseryl-tRNASec kinase (PSTK) phosphorylates Ser-tRNASec to produce the O-phosphoseryl-tRNASec (Sep-tRNASec) substrate that Sep-tRNA:Sec-tRNA synthase (SepSecS) converts to Sec-tRNASec. This study presents a biochemical characterization of Methanocaldococcus jannaschii PSTK, including kinetics of Sep-tRNASec formation (Km for Ser-tRNASec of 40 nM and ATP of 2.6 mM). PSTK binds both Ser-tRNASec and tRNASec with high affinity (Kd values of 53 nM and 39 nM, respectively). The ATPase activity of PSTK may be activated via an induced fit mechanism in which binding of tRNASec specifically stimulates hydrolysis. Albeit with lower activity than ATP, PSTK utilizes GTP, CTP, UTP and dATP as phosphate-donors. Homology with related kinases allowed prediction of the ATPase active site, comprised of phosphate-binding loop (P-loop), Walker B and RxxxR motifs. Gly14, Lys17, Ser18, Asp41, Arg116 and Arg120 mutations resulted in enzymes with decreased activity highlighting the importance of these conserved motifs in PSTK catalysis both in vivo and in vitro. Phylogenetic analysis of PSTK in the context of its ‘DxTN’ kinase family shows that PSTK co-evolved precisely with SepSecS and indicates the presence of a previously unidentified PSTK in Plasmodium species.
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Affiliation(s)
- R Lynn Sherrer
- Department of Molecular Biophysics, Yale University, New Haven, CT 06520-8114, USA
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Araiso Y, Palioura S, Ishitani R, Sherrer RL, O'Donoghue P, Yuan J, Oshikane H, Domae N, Defranco J, Söll D, Nureki O. Structural insights into RNA-dependent eukaryal and archaeal selenocysteine formation. Nucleic Acids Res 2007; 36:1187-99. [PMID: 18158303 PMCID: PMC2275076 DOI: 10.1093/nar/gkm1122] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The micronutrient selenium is present in proteins as selenocysteine (Sec). In eukaryotes and archaea, Sec is formed in a tRNA-dependent conversion of O-phosphoserine (Sep) by O-phosphoseryl-tRNA:selenocysteinyl-tRNA synthase (SepSecS). Here, we present the crystal structure of Methanococcus maripaludis SepSecS complexed with PLP at 2.5 Å resolution. SepSecS, a member of the Fold Type I PLP enzyme family, forms an (α2)2 homotetramer through its N-terminal extension. The active site lies on the dimer interface with each monomer contributing essential residues. In contrast to other Fold Type I PLP enzymes, Asn247 in SepSecS replaces the conserved Asp in binding the pyridinium nitrogen of PLP. A structural comparison with Escherichia coli selenocysteine lyase allowed construction of a model of Sep binding to the SepSecS catalytic site. Mutations of three conserved active site arginines (Arg72, Arg94, Arg307), protruding from the neighboring subunit, led to loss of in vivo and in vitro activity. The lack of active site cysteines demonstrates that a perselenide is not involved in SepSecS-catalyzed Sec formation; instead, the conserved arginines may facilitate the selenation reaction. Structural phylogeny shows that SepSecS evolved early in the history of PLP enzymes, and indicates that tRNA-dependent Sec formation is a primordial process.
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Affiliation(s)
- Yuhei Araiso
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501, Japan
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16
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Förster C, Brauer ABE, Fürste JP, Betzel C, Weber M, Cordes F, Erdmann VA. Superposition of a tRNASer acceptor stem microhelix into the seryl-tRNA synthetase complex. Biochem Biophys Res Commun 2007; 362:415-8. [PMID: 17719008 DOI: 10.1016/j.bbrc.2007.07.178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 07/31/2007] [Indexed: 11/18/2022]
Abstract
Aminoacyl-tRNA synthetases catalyze the formation of aminoacyl-tRNAs. Seryl-tRNA synthetase is a class II synthetase, which depends on rather few and simple identity elements in tRNA(Ser) to determine the amino acid specificity. tRNA(Ser) acceptor stem microhelices can be aminoacylated with serine, which makes this part of the tRNA a valuable tool for investigating the structural motifs in a tRNA(Ser)-seryl-tRNA synthetase complex. A 1.8A-resolution tRNA(Ser) acceptor stem crystal structure was superimposed to a 2.9A-resolution crystal structure of a tRNA(Ser)-seryl-tRNA synthetase complex for a visualization of the binding environment of the tRNA(Ser) microhelix.
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MESH Headings
- Anticodon/chemistry
- Anticodon/metabolism
- Crystallization
- Crystallography, X-Ray
- Models, Molecular
- Nucleic Acid Conformation
- Protein Binding
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/metabolism
- RNA, Transfer, Ser/chemistry
- RNA, Transfer, Ser/metabolism
- Serine-tRNA Ligase/chemistry
- Serine-tRNA Ligase/metabolism
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Affiliation(s)
- C Förster
- Institute of Chemistry and Biochemistry, Free University Berlin, Thielallee 63, 14195 Berlin, Germany
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17
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Abstract
At the time of its discovery four decades ago, the genetic code was viewed as the result of a "frozen accident." Our current knowledge of the translation process and of the detailed structure of its components highlights the roles of RNA structure (in mRNA and tRNA), RNA modification (in tRNA), and aminoacyl-tRNA synthetase diversity in the evolution of the genetic code. The diverse assortment of codon reassignments present in subcellular organelles and organisms of distinct lineages has 'thawed' the concept of a universal immutable code; it may not be accidental that out of more than 140 amino acids found in natural proteins, only two (selenocysteine and pyrrolysine) are known to have been added to the standard 20-member amino acid alphabet. The existence of phosphoseryl-tRNA (in the form of tRNACys and tRNASec) may presage the discovery of other cotranslationally inserted modified amino acids.
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Affiliation(s)
- Alexandre Ambrogelly
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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Yuan J, Palioura S, Salazar JC, Su D, O'Donoghue P, Hohn MJ, Cardoso AM, Whitman WB, Söll D. RNA-dependent conversion of phosphoserine forms selenocysteine in eukaryotes and archaea. Proc Natl Acad Sci U S A 2006; 103:18923-7. [PMID: 17142313 PMCID: PMC1748153 DOI: 10.1073/pnas.0609703104] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The trace element selenium is found in proteins as selenocysteine (Sec), the 21st amino acid to participate in ribosome-mediated translation. The substrate for ribosomal protein synthesis is selenocysteinyl-tRNA(Sec). Its biosynthesis from seryl-tRNA(Sec) has been established for bacteria, but the mechanism of conversion from Ser-tRNA(Sec) remained unresolved for archaea and eukarya. Here, we provide evidence for a different route present in these domains of life that requires the tRNA(Sec)-dependent conversion of O-phosphoserine (Sep) to Sec. In this two-step pathway, O-phosphoseryl-tRNA(Sec) kinase (PSTK) converts Ser-tRNA(Sec) to Sep-tRNA(Sec). This misacylated tRNA is the obligatory precursor for a Sep-tRNA:Sec-tRNA synthase (SepSecS); this protein was previously annotated as SLA/LP. The human and archaeal SepSecS genes complement in vivo an Escherichia coli Sec synthase (SelA) deletion strain. Furthermore, purified recombinant SepSecS converts Sep-tRNA(Sec) into Sec-tRNA(Sec) in vitro in the presence of sodium selenite and purified recombinant E. coli selenophosphate synthetase (SelD). Phylogenetic arguments suggest that Sec decoding was present in the last universal common ancestor. SepSecS and PSTK coevolved with the archaeal and eukaryotic lineages, but the history of PSTK is marked by several horizontal gene transfer events, including transfer to non-Sec-decoding Cyanobacteria and fungi.
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Affiliation(s)
- Jing Yuan
- Departments of *Molecular Biophysics and Biochemistry and
| | | | | | - Dan Su
- Departments of *Molecular Biophysics and Biochemistry and
| | | | | | | | - William B. Whitman
- Department of Microbiology, University of Georgia, Athens, GA 30602-2605
| | - Dieter Söll
- Departments of *Molecular Biophysics and Biochemistry and
- Chemistry, Yale University, New Haven, CT 06520-8114; and
- To whom correspondence should be addressed. E-mail:
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Geslain R, Aeby E, Guitart T, Jones TE, Castro de Moura M, Charrière F, Schneider A, Ribas de Pouplana L. Trypanosoma seryl-tRNA synthetase is a metazoan-like enzyme with high affinity for tRNASec. J Biol Chem 2006; 281:38217-25. [PMID: 17040903 DOI: 10.1074/jbc.m607862200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosomatids are important human pathogens that form a basal branch of eukaryotes. Their evolutionary history is still unclear as are many aspects of their molecular biology. Here we characterize essential components required for the incorporation of serine and selenocysteine into the proteome of Trypanosoma. First, the biological function of a putative Trypanosoma seryl-tRNA synthetase was characterized in vivo. Secondly, the molecular recognition by Trypanosoma seryl-tRNA synthetase of its cognate tRNAs was dissected in vitro. The cellular distribution of tRNA(Sec) was studied, and the catalytic constants of its aminoacylation were determined. These were found to be markedly different from those reported in other organisms, indicating that this reaction is particularly efficient in trypanosomatids. Our functional data were analyzed in the context of a new phylogenetic analysis of eukaryotic seryl-tRNA synthetases that includes Trypanosoma and Leishmania sequences. Our results show that trypanosomatid seryl-tRNA synthetases are functionally and evolutionarily more closely related to their metazoan homologous enzymes than to other eukaryotic enzymes. This conclusion is supported by sequence synapomorphies that clearly connect metazoan and trypanosomatid seryl-tRNA synthetases.
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Affiliation(s)
- Renaud Geslain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) and Institute for Research in Biomedicine, Barcelona, Barcelona Science Park, C/Samitier 1-5, Barcelona 08015, Catalonia, Spain
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Gruic-Sovulj I, Jaric J, Dulic M, Cindric M, Weygand-Durasevic I. Shuffling of discrete tRNASer regions reveals differently utilized identity elements in yeast and methanogenic archaea. J Mol Biol 2006; 361:128-39. [PMID: 16822522 DOI: 10.1016/j.jmb.2006.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 06/05/2006] [Accepted: 06/06/2006] [Indexed: 10/24/2022]
Abstract
Seryl-tRNA synthetases (SerRSs) from methanogenic archaea possess distinct evolutionary origin and show minimal sequence similarity with counterparts from bacteria, eukaryotes and other archaea. Here we show that SerRS from yeast Saccharomyces cerevisiae and archaeon Methanococcus maripaludis (ScSerRS and MmSerRS, respectively) display significantly different ability to serylate heterologous tRNA(Ser). Recognition in yeast was shown to be more stringent than in archaeon. While cross-aminoacylation of M. maripaludis tRNA(Ser) (MmtRNA(Ser)) by yeast SerRS barely occurs, yeast tRNA(Ser) (SctRNA(Ser)) was shown to be a good substrate for heterologous MmSerRS. To investigate the contribution of different tRNA regions for the recognition by yeast and archaeal SerRS, chimeric tRNAs bearing separated domains of SctRNA(Ser) in MmtRNA(Ser) framework were produced by in vitro transcription and subjected to kinetic and gel mobility shift analysis with both enzymes. Generally, the recognition in M. maripaludis seems to be relatively relaxed toward tertiary elements of tRNA(Ser) structure and relies on the direct recognition of identity nucleotides. On the other hand, expression of tRNA(Ser) identity elements in yeast seems to be more sensitive toward surrounding sequence context. In both systems variable arm of tRNA was recognized as a major identity region with a strong influence on SerRS:tRNA binding. Acceptor domain of SctRNA(Ser) was also shown to be important for serylation in yeast. We propose that cognate interactions between N-terminal domain of yeast SerRS and variable region of SctRNA(Ser) place the acceptor stem into the enzyme's active site and lead to increased affinity toward serine and efficient serylation of tRNA. The same effect was not observed in M. maripaludis. Unlike its yeast counterpart, MmSerRS forms only one type of covalent complex with MmtRNA(Ser), regardless of the tRNA/SerRS molar ratio. Stoichiometry of the complex, one tRNA per dimeric SerRS, was revealed by mass spectrometry. Our studies indicate that different SerRS:tRNA recognition mode is utilized by these two systems.
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Affiliation(s)
- Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Croatia
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Bilokapic S, Maier T, Ahel D, Gruic-Sovulj I, Söll D, Weygand-Durasevic I, Ban N. Structure of the unusual seryl-tRNA synthetase reveals a distinct zinc-dependent mode of substrate recognition. EMBO J 2006; 25:2498-509. [PMID: 16675947 PMCID: PMC1478180 DOI: 10.1038/sj.emboj.7601129] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Accepted: 04/11/2006] [Indexed: 11/09/2022] Open
Abstract
Methanogenic archaea possess unusual seryl-tRNA synthetase (SerRS), evolutionarily distinct from the SerRSs found in other archaea, eucaryotes and bacteria. The two types of SerRSs show only minimal sequence similarity, primarily within class II conserved motifs 1, 2 and 3. Here, we report a 2.5 A resolution crystal structure of the atypical methanogenic Methanosarcina barkeri SerRS and its complexes with ATP, serine and the nonhydrolysable seryl-adenylate analogue 5'-O-(N-serylsulfamoyl)adenosine. The structures reveal two idiosyncratic features of methanogenic SerRSs: a novel N-terminal tRNA-binding domain and an active site zinc ion. The tetra-coordinated Zn2+ ion is bound to three conserved protein ligands (Cys306, Glu355 and Cys461) and binds the amino group of the serine substrate. The absolute requirement of the metal ion for enzymatic activity was confirmed by mutational analysis of the direct zinc ion ligands. This zinc-dependent serine recognition mechanism differs fundamentally from the one employed by the bacterial-type SerRSs. Consequently, SerRS represents the only known aminoacyl-tRNA synthetase system that evolved two distinct mechanisms for the recognition of the same amino-acid substrate.
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Affiliation(s)
| | - Timm Maier
- Institute of Molecular Biology and Biophyscis, Swiss Federal Institute of Technology, ETH Zürich, ETH Hoenggerberg, Zürich, Switzerland
| | - Dragana Ahel
- Department of Chemistry, University of Zagreb, Zagreb, Croatia
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Ivana Weygand-Durasevic
- Department of Chemistry, University of Zagreb, Zagreb, Croatia
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb 10 000, Croatia. Tel.: +385 1 460 6230; Fax: +385 1 460 6401; E-mail:
| | - Nenad Ban
- Institute of Molecular Biology and Biophyscis, Swiss Federal Institute of Technology, ETH Zürich, ETH Hoenggerberg, Zürich, Switzerland
- Institute of Molecular Biology and Biophyscis, Swiss Federal Institute of Technology, ETH Zurich, ETH Hoenggerberg, HPK Bld., Zurich 8093, Switzerland. Tel.: +41 1 633 27 85; Fax: +41 1 633 12 46; E-mail:
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23
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Chimnaronk S, Gravers Jeppesen M, Suzuki T, Nyborg J, Watanabe K. Dual-mode recognition of noncanonical tRNAs(Ser) by seryl-tRNA synthetase in mammalian mitochondria. EMBO J 2005; 24:3369-79. [PMID: 16163389 PMCID: PMC1276171 DOI: 10.1038/sj.emboj.7600811] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 08/22/2005] [Indexed: 11/09/2022] Open
Abstract
The secondary structures of metazoan mitochondrial (mt) tRNAs(Ser) deviate markedly from the paradigm of the canonical cloverleaf structure; particularly, tRNA(Ser)(GCU) corresponding to the AGY codon (Y=U and C) is highly truncated and intrinsically missing the entire dihydrouridine arm. None of the mt serine isoacceptors possesses the elongated variable arm, which is the universal landmark for recognition by seryl-tRNA synthetase (SerRS). Here, we report the crystal structure of mammalian mt SerRS from Bos taurus in complex with seryl adenylate at an atomic resolution of 1.65 A. Coupling structural information with a tRNA-docking model and the mutagenesis studies, we have unraveled the key elements that establish tRNA binding specificity, differ from all other known bacterial and eukaryotic systems, are the characteristic extensions in both extremities, as well as a few basic residues residing in the amino-terminal helical arm of mt SerRS. Our data further uncover an unprecedented mechanism of a dual-mode recognition employed to discriminate two distinct 'bizarre' mt tRNAs(Ser) by alternative combination of interaction sites.
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Affiliation(s)
- Sarin Chimnaronk
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
| | | | - Tsutomu Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
| | - Jens Nyborg
- Department of Molecular Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Kimitsuna Watanabe
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
- Present address: Biological Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-42 Aomi, Koto-ku, Tokyo 135-0064, Japan
- Biological Information Research Center, National Institute of Advanced Industrial Science & Technology (AIST), 2-42 Aomi, Koto-ku, Tokyo 135-0064, Japan. Tel.:+81 3 3599 8106; Fax: +81 3 5530 2064; E-mail:
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