tRNA-dependent amino acid discrimination by Escherichia coli valyl-tRNA synthetase

dc.contributor.advisor Jack Horowitz
dc.contributor.author Tardif, Keith
dc.contributor.department Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology (LAS)
dc.date 2018-08-23T06:19:50.000
dc.date.accessioned 2020-06-30T07:19:47Z
dc.date.available 2020-06-30T07:19:47Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 2000
dc.date.issued 2000-01-01
dc.description.abstract <p>Valyl-tRNA synthetase (ValRS) has difficulty discriminating between its cognate amino acid, valine, and structurally similar amino acids, particularly threonine. To minimize translational errors, the enzyme catalyzes a tRNA-dependent editing reaction that prevents accumulation of misacylated tRNA Val. Replacing the universally conserved 3' terminal A of tRNAVal, particularly with pyrimidines (C or U), permits stable misacylation with threonine, alanine, serine, and cysteine. We also observe low levels of aminoacylation of wild type and 3'-end mutants of tRNAVal with isoleucine. ValRS is unable to hydrolytically deacylate misacylated tRNAVal terminating in 3' pyrimidines, but can deacylate tRNAVal terminating in purines (G or A). Evidently, a purine at position 76 of tRNA is necessary for translational editing by ValRS. These misacylated mutant tRNAs act as noncompetitive inhibitors of the aminoacylation reaction. Numerous tRNA mutants have been used to investigate the nucleotides and structural features of tRNA essential for editing. A direct correlation was found between the aminoacylation efficiency of a tRNA and its ability to stimulate the editing reaction, suggesting that editing occurs at the posttransfer step. To identify functional groups on the 3' terminal nucleotide required for function, we replaced the conserved A76 with several different nucleoside analogs and measured their effect on the aminoacylation and editing activity of the tRNA.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/12289/
dc.identifier.articleid 13288
dc.identifier.contextkey 6770095
dc.identifier.doi https://doi.org/10.31274/rtd-180813-13561
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/12289
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/65640
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/12289/r_9977365.pdf|||Fri Jan 14 19:17:19 UTC 2022
dc.subject.disciplines Biochemistry
dc.subject.keywords Biochemistry
dc.subject.keywords biophysics
dc.subject.keywords and molecular biology
dc.subject.keywords Biochemistry
dc.title tRNA-dependent amino acid discrimination by Escherichia coli valyl-tRNA synthetase
dc.type dissertation en_US
dc.type.genre dissertation en_US
dspace.entity.type Publication
relation.isOrgUnitOfPublication faf0a6cb-16ca-421c-8f48-9fbbd7bc3747
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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