1
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Hudec C, Biessy A, Novinscak A, St-Onge R, Lamarre S, Blom J, Filion M. Comparative Genomics of Potato Common Scab-Causing Streptomyces spp. Displaying Varying Virulence. Front Microbiol 2021; 12:716522. [PMID: 34413844 PMCID: PMC8369830 DOI: 10.3389/fmicb.2021.716522] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/13/2021] [Indexed: 11/20/2022] Open
Abstract
Common scab of potato causes important economic losses worldwide following the development of necrotic lesions on tubers. In this study, the genomes of 14 prevalent scab-causing Streptomyces spp. isolated from Prince Edward Island, one of the most important Canadian potato production areas, were sequenced and annotated. Their phylogenomic affiliation was determined, their pan-genome was characterized, and pathogenic determinants involved in their virulence, ranging from weak to aggressive, were compared. 13 out of 14 strains clustered with Streptomyces scabiei, while the last strain clustered with Streptomyces acidiscabies. The toxicogenic and colonization genomic regions were compared, and while some atypical gene organizations were observed, no clear correlation with virulence was observed. The production of the phytotoxin thaxtomin A was also quantified and again, contrary to previous reports in the literature, no clear correlation was found between the amount of thaxtomin A secreted, and the virulence observed. Although no significant differences were observed when comparing the presence/absence of the main virulence factors among the strains of S. scabiei, a distinct profile was observed for S. acidiscabies. Several mutations predicted to affect the functionality of some virulence factors were identified, including one in the bldA gene that correlates with the absence of thaxtomin A production despite the presence of the corresponding biosynthetic gene cluster in S. scabiei LBUM 1485. These novel findings obtained using a large number of scab-causing Streptomyces strains are challenging some assumptions made so far on Streptomyces’ virulence and suggest that other factors, yet to be characterized, are also key contributors.
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Affiliation(s)
- Cindy Hudec
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Adrien Biessy
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC, Canada
| | - Amy Novinscak
- Agassiz Research and Development Centre, Agriculture and Agri-Food Canada, Agassiz, BC, Canada
| | - Renée St-Onge
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Simon Lamarre
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Martin Filion
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC, Canada
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2
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Shepherd J, Ibba M. Bacterial transfer RNAs. FEMS Microbiol Rev 2015; 39:280-300. [PMID: 25796611 DOI: 10.1093/femsre/fuv004] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/21/2015] [Indexed: 11/14/2022] Open
Abstract
Transfer RNA is an essential adapter molecule that is found across all three domains of life. The primary role of transfer RNA resides in its critical involvement in the accurate translation of messenger RNA codons during protein synthesis and, therefore, ultimately in the determination of cellular gene expression. This review aims to bring together the results of intensive investigations into the synthesis, maturation, modification, aminoacylation, editing and recycling of bacterial transfer RNAs. Codon recognition at the ribosome as well as the ever-increasing number of alternative roles for transfer RNA outside of translation will be discussed in the specific context of bacterial cells.
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Affiliation(s)
- Jennifer Shepherd
- Department of Microbiology and the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
| | - Michael Ibba
- Department of Microbiology and the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
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3
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Inokuchi H, Ito R, Sekiguchi T, Sekiguchi M. Search for proteins required for accurate gene expression under oxidative stress: roles of guanylate kinase and RNA polymerase. J Biol Chem 2013; 288:32952-62. [PMID: 24097971 DOI: 10.1074/jbc.m113.507772] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In aerobically growing cells, in which reactive oxygen species are produced, the guanine base is oxidized to 8-oxo-7,8-dihydroguanine, which can pair with adenine as well as cytosine. This mispairing causes alterations in gene expression, and cells possess mechanisms to prevent such outcomes. In Escherichia coli, 8-oxo-7,8-dihydroguanine-related phenotypic suppression of lacZ amber is enhanced by mutations in genes related to the prevention of abnormal protein synthesis under oxidative stress. A genome-wide search for the genes responsible, followed by DNA sequence determination, revealed that specific amino acid changes in guanylate kinase and in the β and β' subunits of RNA polymerase cause elevated levels of phenotypic suppression, specifically under aerobic conditions. The involvement of the DnaB, DnaN, and MsbA proteins, which are involved in DNA replication and in preserving the membrane structure, was also noted. Interactions of these proteins with each other and also with other molecules may be important for preventing errors in gene expression.
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Affiliation(s)
- Hachiro Inokuchi
- From the Frontier Research Center and Department of Biochemistry, Fukuoka Dental College, Fukuoka 814-0193 and
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4
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Sherman JM, Rogers MJ, Söll D. Competition of aminoacyl-tRNA synthetases for tRNA ensures the accuracy of aminoacylation. Nucleic Acids Res 2010; 20:1547-52. [PMID: 16617497 PMCID: PMC312236 DOI: 10.1093/nar/20.7.1547] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The accuracy of protein biosynthesis rests on the high fidelity with which aminoacyl-tRNA synthetases discriminate between tRNAs. Correct aminoacylation depends not only on identity elements (nucleotides in certain positions) in tRNA (1), but also on competition between different synthetases for a given tRNA (2). Here we describe in vivo and in vitro experiments which demonstrate how variations in the levels of synthetases and tRNA affect the accuracy of aminoacylation. We show in vivo that concurrent overexpression of Escherichia coli tyrosyl-tRNA synthetase abolishes misacylation of supF tRNA(Tyr) with glutamine in vivo by overproduced glutaminyl-tRNA synthetase. In an in vitro competition assay, we have confirmed that the overproduction mischarging phenomenon observed in vivo is due to competition between the synthetases at the level of aminoacylation. Likewise, we have been able to examine the role competition plays in the identity of a non-suppressor tRNA of ambiguous identity, tRNA(Glu). Finally, with this assay, we show that the identity of a tRNA and the accuracy with which it is recognized depend on the relative affinities of the synthetases for the tRNA. The in vitro competition assay represents a general method of obtaining qualitative information on tRNA identity in a competitive environment (usually only found in vivo) during a defined step in protein biosynthesis, aminoacylation. In addition, we show that the discriminator base (position 73) and the first base of the anticodon are important for recognition by E. coli tyrosyl-tRNA synthetase.
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Affiliation(s)
- J M Sherman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
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5
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Kisselev LL, Favorova OO. Aminoacyl-tRNA synthetases: sone recent results and achievements. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 40:141-238. [PMID: 4365538 DOI: 10.1002/9780470122853.ch5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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6
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Qian Q, Björk GR. Structural requirements for the formation of 1-methylguanosine in vivo in tRNA(Pro)GGG of Salmonella typhimurium. J Mol Biol 1997; 266:283-96. [PMID: 9047363 DOI: 10.1006/jmbi.1996.0789] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Maturation of tRNA and rRNA and the assembly of the ribosome in all organisms occurs in vivo in a complex pathway in which various proteins such as endo- and exonucleases, tRNA and rRNA modifying enzymes and ribosomal proteins, act concomitantly and temporarily during the maturation process. One class of RNA binding proteins are the tRNA modifying enzymes, which catalyse the formation of various modified nucleosides present in tRNA. Here we analyse the consequences of various alterations in a tRNA on the formation of modified nucleosides in the tRNA and the aminoacylation of it under true in vivo conditions, i.e. in a cell with normal amounts of the tRNA substrate and the tRNA binding protein. We have devised a selection method to obtain mutants of tRNA(Pro)GGG in Salmonella typhimurium that may no longer be a substrate inl vivo for the tRNA(m1G37)methyltransferase. These mutant tRNAs were purified from cells in balanced growth by a solid phase hybridisation technique and the presence of 1-methylguanosine (m1G) in position 37 next to the anticodon was monitored. Of 13 different mutant tRNA(Pro)GGG species analysed, eight of them had a drastically reduced level of m1G. Some of these mutant tRNA species had alterations far from the nucleotide G37 modified by the enzyme; e.g. base-pair disruptions in the first, fourth and eighth (last) base-pair of the acceptor stem, in the D-stem, and in the top of the anticodon stem. The structure of all the mutant tRNA(Pro)GGG species must deviate from the wild-type form, since they all induced +1 frameshifting. Still, tRNA(Pro)GGG from five of the mutants had normal levels of m1G. Thus, only a subset of mutations, all inducing an altered tRNA structure, resulted in m1G deficiency. However, those alterations in tRNA(Pro)GGG, which influenced the tRNA(m1G37)methyltransferase activity, did not affect in vivo the formation of four other modified nucleosides and the aminoacylation of tRNA(Pro)GGG, demonstrating the extreme dependence of the tRNA(m1G37)methyltransferase on an almost perfect three-dimensional structure of the tRNA. We discuss that the conformation of the anticodon loop may be a major determining element for the formation of m1G37 in vivo.
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MESH Headings
- Base Sequence
- DNA, Bacterial/genetics
- Frameshift Mutation
- Guanosine/analogs & derivatives
- Guanosine/genetics
- In Situ Hybridization/methods
- Models, Molecular
- Molecular Sequence Data
- Mutation
- RNA Precursors/genetics
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Transfer, Pro/chemistry
- RNA, Transfer, Pro/genetics
- RNA, Transfer, Pro/metabolism
- Salmonella typhimurium/genetics
- Structure-Activity Relationship
- Substrate Specificity
- Suppression, Genetic
- tRNA Methyltransferases/genetics
- tRNA Methyltransferases/metabolism
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Affiliation(s)
- Q Qian
- Department of Microbiology, Umeå University, Sweden
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7
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Ibba M, Hong KW, Sherman JM, Sever S, Söll D. Interactions between tRNA identity nucleotides and their recognition sites in glutaminyl-tRNA synthetase determine the cognate amino acid affinity of the enzyme. Proc Natl Acad Sci U S A 1996; 93:6953-8. [PMID: 8692925 PMCID: PMC38915 DOI: 10.1073/pnas.93.14.6953] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Sequence-specific interactions between aminoacyl-tRNA synthetases and their cognate tRNAs both ensure accurate RNA recognition and prevent the binding of noncognate substrates. Here we show for Escherichia coli glutaminyl-tRNA synthetase (GlnRS; EC 6.1.1.18) that the accuracy of tRNA recognition also determines the efficiency of cognate amino acid recognition. Steady-state kinetics revealed that interactions between tRNA identity nucleotides and their recognition sites in the enzyme modulate the amino acid affinity of GlnRS. Perturbation of any of the protein-RNA interactions through mutation of either component led to considerable changes in glutamine affinity with the most marked effects seen at the discriminator base, the 10:25 base pair, and the anticodon. Reexamination of the identity set of tRNA(Gln) in the light of these results indicates that its constituents can be differentiated based upon biochemical function and their contribution to the apparent Gibbs' free energy of tRNA binding. Interactions with the acceptor stem act as strong determinants of tRNA specificity, with the discriminator base positioning the 3' end. The 10:25 base pair and U35 are apparently the major binding sites to GlnRS, with G36 contributing both to binding and recognition. Furthermore, we show that E. coli tryptophanyl-tRNA synthetase also displays tRNA-dependent changes in tryptophan affinity when charging a noncognate tRNA. The ability of tRNA to optimize amino acid recognition reveals a novel mechanism for maintaining translational fidelity and also provides a strong basis for the coevolution of tRNAs and their cognate synthetases.
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Affiliation(s)
- M Ibba
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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8
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Sherman JM, Söll D. Aminoacyl-tRNA synthetases optimize both cognate tRNA recognition and discrimination against noncognate tRNAs. Biochemistry 1996; 35:601-7. [PMID: 8555233 DOI: 10.1021/bi951602b] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Specific protein--nucleic acid interactions are usually the product of sequence-dependent hydrogen bonding. However, in the crystal structure of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) in complex with tRNAGln, leucine 136 (Leu136) stabilizes the disruption of the weak first (U1-A72) base pair in tRNAGln by stacking between A72 and G2. We have demonstrated, by a combined in vivo and in vitro mutational analysis, that Leu136 is important for tRNA specificity despite making no hydrogen bonds with tRNAGln. Both more (L136F) and less (L136V, L136M, L136A, and L136T) mischarging mutants of GlnRS have been identified. GlnRS(L136F) is more mischarging and less specific than wild-type GlnRS in vivo, due not to an increased affinity for the noncognate tRNAs but to a decreased affinity for tRNAGln. Also, unlike other mischarging mutants of GlnRS that have been characterized, it does not exhibit generally relaxed tRNA specificity in vivo and mischarges only a subset of the tRNAs tested. A possible sequence preference for a Py1-Pu72/Pu2-Py71 combination is suggested. The L136A/M/T/V mutants are the first GlnRS variants, including wild-type, expressed on pBR322 which no longer mischarge tyrT(UAG) in vivo. We have shown that, while the L136A mutant is less mischarging than wild-type both in vivo and in vitro, it is not more specific as it also exhibits reduced affinity for its cognate glutamine tRNA. On the basis of these results, we suggest that the aminoacyl-tRNA synthetases have evolved to balance cognate tRNA recognition and discrimination against noncognate tRNAs.
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MESH Headings
- Base Sequence
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Glutamate-tRNA Ligase/chemistry
- Glutamate-tRNA Ligase/genetics
- Glutamate-tRNA Ligase/metabolism
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Nucleic Acid Conformation
- Protein Conformation
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Transfer, Gln/chemistry
- RNA, Transfer, Gln/genetics
- RNA, Transfer, Gln/metabolism
- Substrate Specificity
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Affiliation(s)
- J M Sherman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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9
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Martin F, Eriani G, Reinbolt J, Dirheimer G, Gangloff J. Genetic selection for active E.coli amber tRNA(Asn) exclusively led to glutamine inserting suppressors. Nucleic Acids Res 1995; 23:779-84. [PMID: 7708493 PMCID: PMC306759 DOI: 10.1093/nar/23.5.779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Suppressor tRNAs are useful tools for determining identity elements which define recognition of tRNAs in vivo by their cognate aminoacyl-tRNA synthetases. This study was aimed at the isolation of active amber tRNA(Asn). Nineteen mutated tRNA(Asn)CUA having amber suppressor activity were selected by an in vivo genetic screen, and all exclusively inserted glutamine. From analysis of the different mutations it is concluded that glutamine accepting activity was obtained upon reducing the interaction strength between the first base pair of the tRNA(Asn)CUA by direct or indirect effects. Failure to isolate tRNA(Asn)CUA suppressors charged with asparagine as well as other evolutionary related amino acids is discussed.
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Affiliation(s)
- F Martin
- Unité Propre de Recherche 9002 du Centre National de la Recherche Scientifique, Strasbourg, France
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10
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Mechulam Y, Meinnel T, Blanquet S. A family of RNA-binding enzymes. the aminoacyl-tRNA synthetases. Subcell Biochem 1995; 24:323-376. [PMID: 7900181 DOI: 10.1007/978-1-4899-1727-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- Y Mechulam
- Laboratoire de Biochimie, CNRS n. 240, Ecole Polytechnique, Palaiseau, France
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11
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Yan W, Francklyn C. Cytosine 73 is a discriminator nucleotide in vivo for histidyl-tRNA in Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36984-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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12
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Abstract
Correct recognition of transfer RNAs (tRNAs) by aminoacyl-tRNA synthetases is central to the maintenance of translational fidelity. The hypothesis that synthetases recognize anticodon nucleotides was proposed in 1964 and had considerable experimental support by the mid-1970s. Nevertheless, the idea was not widely accepted until relatively recently in part because the methodologies initially available for examining tRNA recognition proved hampering for adequately testing alternative hypotheses. Implementation of new technologies has led to a reasonably complete picture of how tRNAs are recognized. The anticodon is indeed important for 17 of the 20 Escherichia coli isoaccepting groups. For many of the isoaccepting groups, the acceptor stem or position 73 (or both) is important as well.
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Affiliation(s)
- M E Saks
- Division of Biology, California Institute of Technology, Pasadena 91125
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13
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Lee CP, Mandal N, Dyson MR, RajBhandary UL. The discriminator base influences tRNA structure at the end of the acceptor stem and possibly its interaction with proteins. Proc Natl Acad Sci U S A 1993; 90:7149-52. [PMID: 8346229 PMCID: PMC47093 DOI: 10.1073/pnas.90.15.7149] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
For many tRNAs, the discriminator base preceding the CCA sequence at the 3' end is important for aminoacylation. We show that the discriminator base influences the stability of the 1.72 base pair onto which it is stacked. Mutations of the discriminator base from adenosine to cytidine or uridine make the cytidine residue in the C1-G72 base pair of mutant Escherichia coli initiator tRNAs more reactive toward sodium bisulfite, the single-strand-specific reagent. The activity of the enzyme Met-tRNA transformylase toward these and other mutant initiator tRNAs is also consistent with destabilization of the 1.72 base pair in vitro and in vivo. By influencing the strength of the 1.72 base pair, the discriminator base could affect the energetic cost of opening the base pair and modulate the structure of the tRNA near the site of aminoacylation. For some aminoacyl-tRNA synthetases and other proteins that interact with tRNA, these factors could be important for specific recognition and/or formation of the transition state during catalysis.
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Affiliation(s)
- C P Lee
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139-4307
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14
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McClain WH, Schneider J, Gabriel K. Association of tRNA(Gln) acceptor identity with phosphate-sugar backbone interactions observed in the crystal structure of the Escherichia coli glutaminyl-tRNA synthetase-tRNA(Gln) complex. Biochimie 1993; 75:1125-36. [PMID: 8199248 DOI: 10.1016/0300-9084(93)90012-h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We isolated several mutants with nucleotide substitutions in alanine tRNA (tRNA(Ala)) that resulted in glutamine tRNA (tRNA(Gln)) acceptor identity in Escherichia coli. These substitutions were in three regions of tRNA structure not previously associated with tRNA(Gln) acceptor identity. Only the phosphate-sugar backbone moieties of these nucleotides interact with the enzyme in the previously determined X-ray crystal structure of the complex between tRNA(Gln) and glutaminyl-tRNA synthetase. We conclude that these sequence-dependent phosphate-sugar backbone interactions contribute to tRNA(Gln) identity, and argue that the interactions help communicate enzyme recognition of the anticodon to the acceptor end of the tRNA and the catalytic center of the enzyme.
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MESH Headings
- Amino Acyl-tRNA Synthetases/chemistry
- Amino Acyl-tRNA Synthetases/metabolism
- Base Sequence
- Carbohydrate Metabolism
- Computer Simulation
- Crystallization
- Escherichia coli/chemistry
- Escherichia coli/enzymology
- Molecular Sequence Data
- Mutation/genetics
- Nucleic Acid Conformation
- Phosphates/metabolism
- RNA, Transfer, Ala/chemistry
- RNA, Transfer, Ala/genetics
- RNA, Transfer, Gln/chemistry
- RNA, Transfer, Gln/genetics
- RNA, Transfer, Gln/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- W H McClain
- Department of Bacteriology, University of Wisconsin, Madison 53706-1567
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15
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Giegé R, Puglisi JD, Florentz C. tRNA structure and aminoacylation efficiency. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1993; 45:129-206. [PMID: 8341800 DOI: 10.1016/s0079-6603(08)60869-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- R Giegé
- Unité Structure des Macromolécules Biologiques et Mécanismes de Reconnaissance, Institut de Biologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Strasbourg, France
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16
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Wright DJ, Martinis SA, Jahn M, Söll D, Schimmel P. Acceptor stem and anticodon RNA hairpin helix interactions with glutamine tRNA synthetase. Biochimie 1993; 75:1041-9. [PMID: 8199240 DOI: 10.1016/0300-9084(93)90003-b] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The class I glutamine (Gln) tRNA synthetase interacts with the anticodon and acceptor stem of glutamine tRNA. RNA hairpin helices were designed to probe acceptor stem and anticodon stem-loop contacts. A seven-base pair RNA microhelix derived from the acceptor stem of tRNA(Gln) was aminoacylated by Gln tRNA synthetase. Variants of the glutamine acceptor stem microhelix implicated the discriminator base as a major identity element for glutaminylation of the RNA helix. A second RNA microhelix representing the anticodon stem-loop competitively inhibited tRNA(Gln) changing. However, the anticodon stem-loop microhelix did not enhance aminoacylation of the acceptor stem microhelix. Thus, transduction of the anticodon identity signal may require covalent continuity of the tRNA chain to trigger efficient aminoacylation.
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Affiliation(s)
- D J Wright
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139
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17
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Dyson MR, Mandal N, RajBhandary UL. Relationship between the structure and function of Escherichia coli initiator tRNA. Biochimie 1993; 75:1051-60. [PMID: 7515283 DOI: 10.1016/0300-9084(93)90004-c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Through functional studies of mutant tRNAs, we have identified sequence and/or structural features important for specifying the many distinctive properties of E coli initiator tRNA. Many of the mutant tRNAs contain an anticodon sequence change from CAU-->CUA and are now substrates for E coli glutaminyl-tRNA synthetase (GlnRS). We describe here the effect of further mutating the discriminator base 73 and nucleotide 72 at the end of the acceptor stem on: i) recognition of the mutant tRNAs by E coli GlnRS; ii) recognition by E coli methionyl-tRNA transformylase; and iii) activity of the mutant tRNAs in initiation in E coli. For GlnRS recognition, our results are, in general, consistent with interactions found in the crystal structure of the E coli GlnRS-glutamine tRNA complex. The results also support our previous conclusion that formylation of initiator tRNA is important for its function in initiation.
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MESH Headings
- Acyltransferases/chemistry
- Acyltransferases/genetics
- Acyltransferases/metabolism
- Amino Acyl-tRNA Synthetases/chemistry
- Amino Acyl-tRNA Synthetases/genetics
- Amino Acyl-tRNA Synthetases/metabolism
- Base Sequence
- Binding Sites
- Escherichia coli/chemistry
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Hydroxymethyl and Formyl Transferases
- Immunoblotting
- Molecular Sequence Data
- Mutation
- Nucleic Acid Conformation
- Peptide Chain Initiation, Translational
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- RNA, Transfer, Met
- Structure-Activity Relationship
- Substrate Specificity
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Affiliation(s)
- M R Dyson
- Institute of Cell and Molecular Biology, University of Edinburgh, UK
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18
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Sherman JM, Rogers K, Rogers MJ, Söll D. Synthetase competition and tRNA context determine the in vivo identify of tRNA discriminator mutants. J Mol Biol 1992; 228:1055-62. [PMID: 1474577 DOI: 10.1016/0022-2836(92)90314-a] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The discriminator nucleotide (position 73) in tRNA has long been thought to play a role in tRNA identity as it is the only variable single-stranded nucleotide that is found near the site of aminoacylation. For this reason, a complete mutagenic analysis of the discriminator in three Escherichia coli amber suppressor tRNA backgrounds was undertaken; supE and supE-G1C72 glutamine tRNAs, gluA glutamate tRNA and supF tyrosine tRNA. The effect of mutation of the discriminator base on the identity of these tRNAs in vivo was assayed by N-terminal protein sequencing of E. coli dihydrofolate reductase, which is the product of suppression by the mutated amber suppressors, and confirmed by amino acid specific suppression experiments. In addition, suppressor efficiency assays were used to estimate the efficiency of aminoacylation in vivo. Our results indicate that the supE glutamine tRNA context can tolerate multiple mutations (including mutation of the discriminator and first base-pair) and still remain predominantly glutamine-accepting. Discriminator mutants of gluA glutamate tRNA exhibit increased and altered specificity probably due to the reduced ability of other synthetases to compete with glutamyl-tRNA synthetase. In the course of these experiments, a glutamate-specific mutant amber suppressor, gluA-A73, was created. Finally, in the case of supF tyrosine tRNA, the discriminator is an important identity element with partial to complete loss of tyrosine specificity resulting from mutation at this position. It is clear from these experiments that it may not be possible to assign a specific role in tRNA identity to the discriminator. The identity of a tRNA in vivo is determined by competition among aminoacyl-tRNA synthetases, which is in turn modulated by the nucleotide substitution as well as the tRNA context.
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MESH Headings
- Amino Acids/metabolism
- Amino Acyl-tRNA Synthetases/metabolism
- Binding, Competitive
- Escherichia coli/genetics
- Genes, Suppressor/genetics
- Mutation
- Protein Biosynthesis
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- RNA, Transfer, Gln/genetics
- RNA, Transfer, Gln/metabolism
- RNA, Transfer, Glu/genetics
- RNA, Transfer, Glu/metabolism
- RNA, Transfer, Tyr/genetics
- RNA, Transfer, Tyr/metabolism
- Structure-Activity Relationship
- Tetrahydrofolate Dehydrogenase/biosynthesis
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Affiliation(s)
- J M Sherman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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19
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Perret V, Florentz C, Puglisi JD, Giegé R. Effect of conformational features on the aminoacylation of tRNAs and consequences on the permutation of tRNA specificities. J Mol Biol 1992; 226:323-33. [PMID: 1640453 DOI: 10.1016/0022-2836(92)90950-o] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The structure and function of in vitro transcribed tRNA(Asp) variants with inserted conformational features characteristic of yeast tRNA(Phe), such as the length of the variable region or the arrangement of the conserved residues in the D-loop, have been investigated. Although they exhibit significant conformational alterations as revealed by Pb2+ treatment, these variants are still efficiently aspartylated by yeast aspartyl-tRNA synthetase. Thus, this synthetase can accommodate a variety of tRNA conformers. In a second series of variants, the identity determinants of yeast tRNA(Phe) were transplanted into the previous structural variants of tRNA(Asp). The phenylalanine acceptance of these variants improves with increasing the number of structural characteristics of tRNA(Phe), suggesting that phenylalanyl-tRNA synthetase is sensitive to the conformational frame embedding the cognate identity nucleotides. These results contrast with the efficient transplantation of tRNA(Asp) identity elements into yeast tRNA(Phe). This indicates that synthetases respond differently to the detailed conformation of their tRNA substrates. Efficient aminoacylation is not only dependent on the presence of the set of identity nucleotides, but also on a precise conformation of the tRNA.
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MESH Headings
- Aspartate-tRNA Ligase/metabolism
- Base Sequence
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phenylalanine-tRNA Ligase/metabolism
- RNA, Fungal/metabolism
- RNA, Fungal/ultrastructure
- RNA, Transfer, Asp/metabolism
- RNA, Transfer, Asp/ultrastructure
- RNA, Transfer, Phe/metabolism
- RNA, Transfer, Phe/ultrastructure
- Saccharomyces cerevisiae
- Structure-Activity Relationship
- Substrate Specificity
- Transfer RNA Aminoacylation
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Affiliation(s)
- V Perret
- Laboratoire de Biochimie, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
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20
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Normanly J, Ollick T, Abelson J. Eight base changes are sufficient to convert a leucine-inserting tRNA into a serine-inserting tRNA. Proc Natl Acad Sci U S A 1992; 89:5680-4. [PMID: 1608979 PMCID: PMC49356 DOI: 10.1073/pnas.89.12.5680] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Each aminoacyl-tRNA synthetase must functionally distinguish its cognate tRNAs from all others. We have determined the minimum number of changes required to transform a leucine amber suppressor tRNA to serine identity. Eight changes are required. These are located in the acceptor stem and in the D stem.
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Affiliation(s)
- J Normanly
- Division of Biology, California Institute of Technology, Pasadena 91125
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21
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Sherman JM, Rogers MJ, Söll D. Competition of aminoacyl-tRNA synthetases for tRNA ensures the accuracy of aminoacylation. Nucleic Acids Res 1992; 20:2847-52. [PMID: 1377381 PMCID: PMC336931 DOI: 10.1093/nar/20.11.2847] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The accuracy of protein biosynthesis rests on the high fidelity with which aminoacyl-tRNA synthetases discriminate between tRNAs. Correct aminoacylation depends not only on identity elements (nucleotides in certain positions) in tRNA (1), but also on competition between different synthetases for a given tRNA (2). Here we describe in vivo and in vitro experiments which demonstrate how variations in the levels of synthetases and tRNA affect the accuracy of aminoacylation. We show in vivo that concurrent overexpression of Escherichia coli tyrosyl-tRNA synthetase abolishes misacylation of supF tRNA(Tyr) with glutamine in vivo by overproduced glutaminyl-tRNA synthetase. In an in vitro competition assay, we have confirmed that the overproduction mischarging phenomenon observed in vivo is due to competition between the synthetases at the level of aminoacylation. Likewise, we have been able to examine the role competition plays in the identity of a non-suppressor tRNA of ambiguous identity, tRNA(Glu). Finally, with this assay, we show that the identity of a tRNA and the accuracy with which it is recognized depend on the relative affinities of the synthetases for the tRNA. The in vitro competition assay represents a general method of obtaining qualitative information on tRNA identity in a competitive environment (usually only found in vivo) during a defined step in protein biosynthesis, aminoacylation. In addition, we show that the discriminator base (position 73) and the first base of the anticodon are important for recognition by E. coli tyrosyl-tRNA synthetase.
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Affiliation(s)
- J M Sherman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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22
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Englisch-Peters S, Conley J, Plumbridge J, Leptak C, Söll D, Rogers MJ. Mutant enzymes and tRNAs as probes of the glutaminyl-tRNA synthetase: tRNA(Gln) interaction. Biochimie 1991; 73:1501-8. [PMID: 1725262 DOI: 10.1016/0300-9084(91)90184-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This paper focuses on several aspects of the specificity of mutants of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) and tRNA(Gln). Temperature-sensitive mutants located in glnS, the gene for GlnRS, have been described previously. The mutations responsible for the temperature-sensitive phenotype were analyzed, and pseudorevertants of these mutants isolated and characterized. The nature of these mutations is discussed in terms of their location in the three-dimensional structure of the tRNA(Gln).GlnRS complex. In order to characterize the specificity of the aminoacylation reaction, mutant tRNA(Gln) species were synthesized with either a 2'-deoxy AMP or 3'-deoxy AMP as their 3'-terminal nucleotide. Subsequent assays for aminoacylation and ATP/PPi exchange activity established the esterification of glutamine to the 2'-hydroxyl of the terminal adenosine; there is no glutaminylation of the 3'-OH group. This correlates with the classification of GlnRS as a class I aminoacyl-tRNA synthetase. Mutations in tRNA(Gln) are discussed which affect the recognition of GlnRS and the current concept of glutamine identity in E coli is reviewed.
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Affiliation(s)
- S Englisch-Peters
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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23
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Direct analysis of aminoacylation levels of tRNAs in vivo. Application to studying recognition of Escherichia coli initiator tRNA mutants by glutaminyl-tRNA synthetase. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54288-5] [Citation(s) in RCA: 305] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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24
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Jahn M, Rogers MJ, Söll D. Anticodon and acceptor stem nucleotides in tRNA(Gln) are major recognition elements for E. coli glutaminyl-tRNA synthetase. Nature 1991; 352:258-60. [PMID: 1857423 DOI: 10.1038/352258a0] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The correct attachment of amino acids to their corresponding (cognate) transfer RNA catalysed by aminoacyl-tRNA synthetases is a key factor in ensuring the fidelity of protein biosynthesis. Previous studies have demonstrated that the interaction of Escherichia coli tRNA(Gln) with glutaminyl-tRNA synthetase (GlnRS) provides an excellent system to study this highly specific recognition process, also referred to as 'tRNA identity'. Accurate acylation of tRNA depends mainly on two principles: a set of nucleotides in the tRNA molecule (identity elements) responsible for proper discrimination by aminoacyl-tRNA synthetases and competition between different synthetases for tRNAs. Elements of glutamine identity are located in the anticodon and in the acceptor stem region, including the discriminator base. We report here the production of more than 20 tRNA(2Gln) mutants at positions likely to be involved in tRNA discrimination by the enzyme. Unmodified tRNA, containing the wild-type anticodon and U or G at its 5'-terminus, can be aminocylated by GlnRS with similar kinetic parameters to native tRNA(2Gln). By in vitro aminoacylation the mutant tRNAs showed decreases of up to 3 x 10(5)-fold in the specificity constant (kcat/KM)14 with the major contribution of kcat. Despite these large changes, some of these mutant tRNAs are efficient amber suppressors in vivo. Our results show that strong elements for glutamine identity reside in the anticodon region and in positions 2 and 3 of the acceptor stem, and that the contribution of different identity elements to the overall discrimination varies significantly. We discuss our data in the light of the crystal structure of the GlnRS:tRNA(Gln) complex.
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Affiliation(s)
- M Jahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511
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25
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Recognition of †RNAs by Aminoacyl-†RNA Synthetases. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1991. [DOI: 10.1016/s0079-6603(08)60006-9] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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26
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Himeno H, Hasegawa T, Ueda T, Watanabe K, Shimizu M. Conversion of aminoacylation specificity from tRNA(Tyr) to tRNA(Ser) in vitro. Nucleic Acids Res 1990; 18:6815-9. [PMID: 2263446 PMCID: PMC332736 DOI: 10.1093/nar/18.23.6815] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The discrimination mechanism between tRNA(Ser) and tRNA(Tyr) was studied using various in vitro transcripts of E. coli tRNATyr variants. The insertion of only two nucleotides into the variable stem of tRNA(Tyr) generates serine charging activity. The acceptor activities of some of the tRNA(Tyr) mutants with insertions in the long variable arm were enhanced by changes in nucleotides at positions 9 and/or 20B, which are possible elements for dictating the orientation of the long variable arm. These findings suggest that the long variable arm is involved in recognition by seryl-tRNA synthetase in spite of sequence and length variations shown within tRNA(Ser) isoacceptors, and eventually serves as a determinant for selection from other tRNA species. Changing the anticodon from GUA to the serine anticodon GGA resulted in a marked decrease in tyrosine charging activity, but this mutant did not show any serine charging activity. The discriminator base, the fourth base from the 3' end of tRNA, was also important for aminoacylation with tyrosine. Complete specificity change in vitro was facilitated by insertion of three nucleotides into the variable arm plus two nucleotide changes at positions 9 and 73.
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Affiliation(s)
- H Himeno
- Institute of Space and Astronautical Science, Kanagawa, Japan
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27
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Söll D. The accuracy of aminoacylation--ensuring the fidelity of the genetic code. EXPERIENTIA 1990; 46:1089-96. [PMID: 2253707 DOI: 10.1007/bf01936918] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The fidelity of protein biosynthesis rests not only on the proper interaction of the messenger RNA codon with the anticodon of the tRNA, but also on the correct attachment of amino acids to their corresponding (cognate) transfer RNA (tRNA) species. This process is catalyzed by the aminoacyl-tRNA synthetases which discriminate with remarkable selectivity amongst many structurally similar tRNAs. The basis for this highly specific recognition of tRNA by these enzymes (also referred to as 'tRNA identity') is currently being elucidated by genetic, biochemical and biophysical techniques. At least two factors are important in determining the accuracy of aminoacylation: a) 'identity elements' in tRNA denote nucleotides in certain positions crucial for protein interactions determining specificity, and b) the occurrence in vivo of competition between synthetases for a particular tRNA which may have ambiguous identity.
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Affiliation(s)
- D Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511
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28
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McClain WH, Foss K, Jenkins RA, Schneider J. Nucleotides that determine Escherichia coli tRNA(Arg) and tRNA(Lys) acceptor identities revealed by analyses of mutant opal and amber suppressor tRNAs. Proc Natl Acad Sci U S A 1990; 87:9260-4. [PMID: 2251270 PMCID: PMC55144 DOI: 10.1073/pnas.87.23.9260] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have constructed an opal suppressor system in Escherichia coli to complement an existing amber suppressor system to study the structural basis of tRNA acceptor identity, particularly the role of middle anticodon nucleotide at position 35. The opal suppressor tRNA contains a UCA anticodon and the mRNA of the suppressed protein (which is easily purified and sequenced) contains a UGA nonsense triplet. Opal suppressor tRNAs of two tRNA(Arg) isoacceptor sequences each gave arginine in the suppressed protein, while the corresponding amber suppressors with U35 in their CUA anticodons each gave arginine plus a second amino acid in the suppressed protein. Since C35 but not U35 is present in the anticodon of wild-type tRNA(Arg) molecules, while the first anticodon position contains either C34 or U34, these results establish that C35 contributes to tRNA(Arg) acceptor identity. Initial characterizations of opal suppressor tRNA(Arg) mutants by suppression efficiency measurements suggest that the fourth nucleotide from the 3' end of tRNA(Arg) (A73 or G73 in different isoacceptors) also contributes to tRNA(Arg) acceptor identity. Wild-type and mutant versions of opal and amber tRNA(Lys) suppressors were examined, revealing that U35 and A73 are important determinants of tRNA(Lys) acceptor identity. Several possibilities are discussed for the general significance of having tRNA acceptor identity in the same positions in different tRNA acceptor types, as exemplified by positions 35 and 73 in tRNA(Arg) and tRNA(Lys).
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Affiliation(s)
- W H McClain
- Department of Bacteriology, University of Wisconsin, Madison 53706-1567
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29
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Steitz TA. Structural studies of protein-nucleic acid interaction: the sources of sequence-specific binding. Q Rev Biophys 1990; 23:205-80. [PMID: 2204954 DOI: 10.1017/s0033583500005552] [Citation(s) in RCA: 460] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Structural studies of DNA-binding proteins and their complexes with DNA have proceeded at an accelerating pace in recent years due to important technical advances in molecular genetics, DNA synthesis, protein crystallography and nuclear magnetic resonance. The last major review on this subject by Pabo & Sauer (1984) summarized the structural and functional studies of the three sequence-specific DNA-binding proteins whose crystal structures were then known, theE. colicatabolite gene activator protein (CAP) (McKay & Steitz, 1981; McKayet al.1982; Weber & Steitz, 1987), acrorepressor from phage λ (Andersonet al.1981), and the DNA-binding proteolytic fragment ofλcIrepressor protein (Pabo & Lewis, 1982) Although crystallographic studies of theE. coli lacrepressor protein were initiated as early as 1971 when it was the only regulatory protein available in sufficient quantities for structural studies (Steitzet al.1974), little was established about the structural aspects of DNA-binding proteins until the structure of CAP was determined in 1980 followed shortly thereafter by the structure ofλcrorepressor and subsequently that of the λ repressor fragment. There are now determined at high resolution the crystal structures of seven prokaryotic gene regulatory proteins or fragments [CAP,λcro,λcIrepressor fragment, 434 repressor fragment (Andersonet al.1987), 434crorepressor (Wolbergeret al.1988),E. coli trprepressor (Schevitzet al.1985),E. coli metrepressor (Raffertyet al.1989)],EcoRI restriction endonuclease (McClarinet al.1986), DNAse I (Suck & Ofner, 1986), the catalytic domain of γδ resolvase (Hatfullet al.1989) and two sequence-independent double-stranded DNA-binding proteins [the Klenow fragment ofE. coliDNA polymerase I (Olliset al.1985) and theE. coliHu protein (Tanakaet al., 1984)].
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Affiliation(s)
- T A Steitz
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University
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30
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Rogers MJ, Söll D. Inaccuracy and the recognition of tRNA. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1990; 39:185-208. [PMID: 2247608 DOI: 10.1016/s0079-6603(08)60627-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- M J Rogers
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511
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31
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Perona JJ, Swanson RN, Rould MA, Steitz TA, Söll D. Structural basis for misaminoacylation by mutant E. coli glutaminyl-tRNA synthetase enzymes. Science 1989; 246:1152-4. [PMID: 2686030 DOI: 10.1126/science.2686030] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A single-site mutant of Escherichia coli glutaminyl-synthetase (D235N, GlnRS7) that incorrectly acylates in vivo the amber suppressor supF tyrosine transfer RNA (tRNA(Tyr] with glutamine has been described. Two additional mutant forms of the enzyme showing this misacylation property have now been isolated in vivo (D235G, GlnRS10; I129T, GlnRS15). All three mischarging mutant enzymes still retain a certain degree of tRNA specificity; in vivo they acylate supE glutaminyl tRNA (tRNA(Gln] and supF tRNA(Tyr) but not a number of other suppressor tRNA's. These genetic experiments define two positions in GlnRS where amino acid substitution results in a relaxed specificity of tRNA discrimination. The crystal structure of the GlnRS:tRNA(Gln) complex provides a structural basis for interpreting these data. In the wild-type enzyme Asp235 makes sequence-specific hydrogen bonds through its side chain carboxylate group with base pair G3.C70 in the minor groove of the acceptor stem of the tRNA. This observation implicates base pair 3.70 as one of the identity determinants of tRNA(Gln). Isoleucine 129 is positioned adjacent to the phosphate of nucleotide C74, which forms part of a hairpin structure adopted by the acceptor end of the complexed tRNA molecule. These results identify specific areas in the structure of the complex that are critical to accurate tRNA discrimination by GlnRS.
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Affiliation(s)
- J J Perona
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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32
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Rould MA, Perona JJ, Söll D, Steitz TA. Structure of E. coli glutaminyl-tRNA synthetase complexed with tRNA(Gln) and ATP at 2.8 A resolution. Science 1989; 246:1135-42. [PMID: 2479982 DOI: 10.1126/science.2479982] [Citation(s) in RCA: 673] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The crystal structure of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) complexed with its cognate glutaminyl transfer RNA (tRNA(Gln] and adenosine triphosphate (ATP) has been derived from a 2.8 angstrom resolution electron density map and the known protein and tRNA sequences. The 63.4-kilodalton monomeric enzyme consists of four domains arranged to give an elongated molecule with an axial ratio greater than 3 to 1. Its interactions with the tRNA extend from the anticodon to the acceptor stem along the entire inside of the L of the tRNA. The complexed tRNA retains the overall conformation of the yeast phenylalanine tRNA (tRNA(Phe] with two major differences: the 3' acceptor strand of tRNA(Gln) makes a hairpin turn toward the inside of the L, with the disruption of the final base pair of the acceptor stem, and the anticodon loop adopts a conformation not seen in any of the previously determined tRNA structures. Specific recognition elements identified so far include (i) enzyme contacts with the 2-amino groups of guanine via the tRNA minor groove in the acceptor stem at G2 and G3; (ii) interactions between the enzyme and the anticodon nucleotides; and (iii) the ability of the nucleotides G73 and U1.A72 of the cognate tRNA to assume a conformation stabilized by the protein at a lower free energy cost than noncognate sequences. The central domain of this synthetase binds ATP, glutamine, and the acceptor end of the tRNA as well as making specific interactions with the acceptor stem.2+t is
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Affiliation(s)
- M A Rould
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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33
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Seong BL, Lee CP, RajBhandary UL. Suppression of Amber Codons in Vivo as Evidence That Mutants Derived from Escherichia coli Initiator tRNA Can Act at the Step of Elongation in Protein Synthesis. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)83376-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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34
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Sampson JR, DiRenzo AB, Behlen LS, Uhlenbeck OC. Nucleotides in yeast tRNAPhe required for the specific recognition by its cognate synthetase. Science 1989; 243:1363-6. [PMID: 2646717 DOI: 10.1126/science.2646717] [Citation(s) in RCA: 155] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An analysis of the aminoacylation kinetics of unmodified yeast tRNAPhe mutants revealed that five single-stranded nucleotides are important for its recognition by yeast phenylalanyl-tRNA synthetase, provided they were positioned correctly in a properly folded tRNA structure. When four other tRNAs were changed to have these five nucleotides, they became near-normal substrates for the enzyme.
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Affiliation(s)
- J R Sampson
- Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309
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35
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McClain WH, Chen YM, Foss K, Schneider J. Association of transfer RNA acceptor identity with a helical irregularity. Science 1988; 242:1681-4. [PMID: 2462282 DOI: 10.1126/science.2462282] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The aminoacylation specificity ("acceptor identity") of transfer RNAs (tRNAs) has previously been associated with the position of particular nucleotides, as opposed to distinctive elements of three-dimensional structure. The contribution of a G.U wobble pair in the acceptor helix of tRNA(Ala) to acceptor identity was examined with synthetic amber suppressor tRNAs in Escherichia coli. The acceptor identity was not affected by replacing the G.U wobble pair in tRNA(Ala) with a G.A, C.A, or U.U wobble pair. Furthermore, a tRNA(Ala) acceptor identity was conferred on tRNA(Lys) when the same site in the acceptor helix was replaced with any of several wobble pairs. Additional data with tRNA(Ala) show that a substantial acceptor identity was retained when the G.U wobble pair was translocated to another site in the acceptor helix. These results suggest that the G.U wobble pair induces an irregularity in the acceptor helix of tRNA(Ala) to match a complementary structure in the aminoacylating enzyme.
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Affiliation(s)
- W H McClain
- Department of Bacteriology, University of Wisconsin, Madison 53706
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36
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Rogers MJ, Söll D. Discrimination between glutaminyl-tRNA synthetase and seryl-tRNA synthetase involves nucleotides in the acceptor helix of tRNA. Proc Natl Acad Sci U S A 1988; 85:6627-31. [PMID: 3045821 PMCID: PMC282030 DOI: 10.1073/pnas.85.18.6627] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Analysis of the in vivo amber suppressor activity of mutants derived from two Escherichia coli serine tRNAs shows that substitution of 2 base pairs in the acceptor helix changes a serine suppressor tRNA to an efficient glutamine acceptor. Determination of the amino acid inserted in vivo into protein by this tRNA shows that these changes reduce the tRNA recognition by seryl-tRNA synthetase while increasing that of glutaminyl-tRNA synthetase. This implies that misaminoacylation in vivo is dependent on the competition by different synthetases for the tRNA. In addition, the "translational efficiency" of tRNA is an integral part in observing misaminoacylation in vivo.
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Affiliation(s)
- M J Rogers
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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37
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Affiliation(s)
- L H Schulman
- Department of Developmental Biology and Cancer, Albert Einstein College of Medicine, Bronx, New York 10461
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38
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Hou YM, Schimmel P. A simple structural feature is a major determinant of the identity of a transfer RNA. Nature 1988; 333:140-5. [PMID: 3285220 DOI: 10.1038/333140a0] [Citation(s) in RCA: 477] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Analysis of a series of mutants of an Escherichia coli alanine transfer RNA shows that substitution of a single G-U base pair in the acceptor helix eliminates aminoacylation with alanine in vivo and in vitro. Introduction of that base pair into the analogous position of a cysteine and a phenylalanine transfer RNA confers upon each the ability to be aminoacylated with alanine. Thus, as little as a single base pair can direct an amino acid to a specific transfer RNA.
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Affiliation(s)
- Y M Hou
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139
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Abstract
A leucine transfer RNA has been transformed into a serine transfer RNA by changing 12 nucleotides. This result indicates that a limited set of residues determine tRNA identity.
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Abstract
Several addition and deletion mutations were constructed in the region of the gene for Escherichia coli tRNATyr su+3 corresponding to the dihydrouracil loop of the mature tRNA. None of these resulting mutants had detectable suppressor function compared to the parent gene yet some directed the synthesis of mature tRNA. These latter mutants may affect the ability of the tRNA to be aminoacylated or to interact with the translational machinery on the ribosome.
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Ackerman EJ, Joachimiak A, Klinghofer V, Sigler PB. Directly photocrosslinked nucleotides joining transfer RNA to aminoacyl-tRNA synthetase in methionine and tyrosine systems. J Mol Biol 1985; 181:93-102. [PMID: 2580097 DOI: 10.1016/0022-2836(85)90327-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have used ultraviolet photocrosslinking and 32P post-labeling to help define the contact surface between transfer RNAs and aminoacyl-tRNA synthetases for the methionine and tyrosine systems. Photocrosslinking between tRNAs and synthetases is shown to occur only in cognate complexes. The increased sensitivity of our procedures reduces the amounts of interacting macromolecules and permits lower ultraviolet light doses, thereby minimizing radiation damage. These procedures have detected crosslinks only within the 3'-terminal RNase T1 fragments in yeast tRNAMeti and Escherichia coli tRNATyr2; and although the photoadducts were unstable, we have identified the crosslinked nucleotides. These crosslinks occur at positions C74 and A76 in yeast tRNAMeti and position U64 in E. coli tRNATyr1&2 (conventional tRNA numbering system of Gauss & Sprinzl, 1981). This work demonstrates that even labile photocrosslinks can be exploited for mapping crosslinked nucleotides.
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42
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Inokuchi H, Hoben P, Yamao F, Ozeki H, Söll D. Transfer RNA mischarging mediated by a mutant Escherichia coli glutaminyl-tRNA synthetase. Proc Natl Acad Sci U S A 1984; 81:5076-80. [PMID: 6382258 PMCID: PMC391640 DOI: 10.1073/pnas.81.16.5076] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We have isolated mutations in the Escherichia coli glnS gene encoding glutaminyl-tRNA synthetase [GlnS; L-glutamine:tRNAGln ligase (AMP-forming), EC 6.1.1.18] that give rise to gene products with altered specificity for tRNA and are designated "mischarging" enzymes. These were produced by nitrosoguanine mutagenesis of the glnS gene carried on a transducing phage (lambda pglnS+). We then selected for mischarging of su+3 tRNATyr with glutamine by requiring suppression of a glutamine-requiring beta-galactosidase amber mutation (lacZ1000). Three independently isolated mutants (glnS7, glnS8, and glnS9) were characterized by genetic and biochemical means. The enzymes encoded by glnS7, glnS8, and glnS9 appear to be highly selective for su+3 tRNATyr, because in vivo mischarging of other amber suppressor tRNAs was not detected. The GlnS mutants described here retain their capacity to correctly aminoacylate tRNAGln. All three independently isolated mutant genes encode proteins with isoelectric points that differ from those of the wild-type enzyme but are identical to each other. This suggests that only a single site in the enzyme structure is altered to give the observed mischarging properties. In vitro aminoacylation reactions with purified GlnS7 protein show that this enzyme can also mischarge some tRNA species lacking the amber anticodon. This is an example of mischarging phenotype conferred by a mutation in an aminoacyl-tRNA synthetase gene; the results are discussed in the context of earlier genetic studies with mutant tRNAs.
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Rydén SM, Isaksson LA. A temperature-sensitive mutant of Escherichia coli that shows enhanced misreading of UAG/A and increased efficiency for some tRNA nonsense suppressors. MOLECULAR & GENERAL GENETICS : MGG 1984; 193:38-45. [PMID: 6419024 DOI: 10.1007/bf00327411] [Citation(s) in RCA: 114] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A spontaneous mutant was isolated that harbors a weak suppressing activity towards a UAG mutation, together with an inability to grow at 43 degrees C in rich medium. The mutation is shown to be associated with an increased misreading of UAG at certain codon contexts and UAA. UGA, missense or frameshift mutations do not appear to be misread to a similar extent. The mutation gives an increased efficiency to several amber tRNA suppressors without increasing their ambiguity towards UAA. The ochre suppressors SuB and Su5 are stimulated in their reading of both UAG and UAA with preference for UAG. An opal suppressor is not affected. The effect of the mutation on the efficiency of amber and ochre suppressors is dependent on the codon context of the nonsense codon. The mutated gene (uar) has been mapped and found to be recessive both with respect to suppressor-enhancing ability as well as for temperature sensitivity. The phenotype is partly suppressed by the ochre suppressor SuC. It is suggested that uar codes for a protein, which is involved in translational termination at UAG and UAA stop codons.
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Seed B. Purification of genomic sequences from bacteriophage libraries by recombination and selection in vivo. Nucleic Acids Res 1983; 11:2427-45. [PMID: 6856467 PMCID: PMC325894 DOI: 10.1093/nar/11.8.2427] [Citation(s) in RCA: 193] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cloned genes have been purified from recombinant DNA bacteriophage libraries by a method exploiting homologous reciprocal recombination in vivo. In this method 'probe' sequences are inserted in a very small plasmid vector and introduced into recombination-proficient bacterial cells. Genomic bacteriophage libraries are propagated on the cells, and phage bearing sequences homologous to the probe acquire an integrated copy of the plasmid by reciprocal recombination. Phage bearing integrated plasmids can be purified from the larger pool of phage lacking plasmid integrates by growth under the appropriate selective conditions.
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Feinstein SI, Altman S. Unusual suppression properties of lysogens containing derivatives of phi 80 psu3+. MOLECULAR & GENERAL GENETICS : MGG 1982; 187:347-53. [PMID: 6817031 DOI: 10.1007/bf00331142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Nonsense codon suppressing lysogens of E. coli have been made using phi 80 psu3+-A2 and phi 80 psuoc+-A2, heat-sensitive amber and ochre suppressing derivatives, respectively, of bacteriophage phi 80. The various lysogens selected differ in strength of suppression as well as in heat sensitivity of suppressor function. Heat-resistant derivatives, some still carrying the A2 mutation, can be selected from the heat sensitive parents. Mapping experiments indicate that the phi 80 derivatives integrate at the tyrTV locus, which contains two copies of tRNA1Tyr. The origin of the various suppressor phenotypes appears to be related to the great variety of distinctive recombination events possible either between the incoming tRNA1Tyr gene and the host copies, or among the three copies of this gene in the lysogens.
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The effect of bisulfite-induced C to U transitions on aminoacylation of Escherichia coli glycine tRNA. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34596-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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A mutation in the tRNAAsp gene from yeast mitochondria. Effects on RNA and protein synthesis. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68687-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Knowlton RG, Soll L, Yarus M. Dual specificity of su+ 7 tRNA. Evidence for translational discrimination. J Mol Biol 1980; 139:705-20. [PMID: 6997500 DOI: 10.1016/0022-2836(80)90056-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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49
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Inokuchi H, Kodaira M, Yamao F, Ozeki H. Identification of transfer RNA suppressors in Escherichia coli. II. Duplicate genes for tRNA2Gln. J Mol Biol 1979; 132:663-77. [PMID: 160950 DOI: 10.1016/0022-2836(79)90381-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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50
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Stern L, Schulman LH. Role of anticodon bases in aminoacylation of Escherichia coli methionine transfer RNAs. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(17)39972-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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