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@article{,

title = {The modified wobble base inosine in yeast tRNAIle is a positive determinant for aminoacylation by isoleucyl-tRNA synthetase},

author = {B Senger and S Auxilien and U Englisch and F Cramer and F Fasiolo},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9204872},

isbn = {9204872},

year  = {1997},

date = {1997-01-01},

journal = {Biochemistry},

volume = {36},

number = {27},

pages = {8269-8275},

abstract = {Earlier work by two independent groups has established the fact that anticodons GAU and LAU of Escherichia coli tRNAIle isoacceptors play a critical role in the tRNA identity. Yeast possesses two isoleucine transfer RNAs, a major one with anticodon IAU and a minor one with anticodon PsiAPsi which are derived from the post-transcriptional modification of AAU and UAU gene sequences, respectively. We present direct evidence which reveals that inosine is a positive determinant for yeast isoleucyl-tRNA synthetase. We also show that yeast tRNAMet with guanosine at the wobble position becomes aminoacylated with isoleucine while methionine acceptance is lost. As inosine and guanosine share the 6-keto and the N-1 hydrogen groups, this suggests that these hydrogen donor and acceptor groups are determinants for isoleucine specificity. The role of the minor tRNAIle anticodon pseudouridines in tRNA isoleucylation could not be tested directly but was deduced from a 40-fold decrease in the activity of the unmodified transcript. The presence of the NHCO structure in guanosine, inosine, pseudouridine, and lysidine suggests a unifying model of wobble base recognition by the yeast and E. coli isoleucyl-tRNA synthetase. In contrast to lysidine which switches the identity of the tRNA from methionine to isoleucine [Muramatsu, T., Nishikawa, K., Nemoto, F., Kuchino, Y., Nishimura, S., Miyazawa, T., & Yokoyama, S. (1988) Nature 336, 179-181], pseudouridine-34 does not modify the specificity of the yeast minor tRNAIle since U-34 is a strong negative determinant for yeast MetRS. Therefore, the major role of Psi-34 (in combination with Psi-36 or not) is likely in isoleucine AUA codon specificity and translational fidelity.},

note = {0006-2960 

Journal Article},

keywords = {Acylation  Anticodon  Base Sequence  Escherichia coli/genetics  Inosine/*chemistry/metabolism  Isoleucine-tRNA Ligase/*metabolism  Molecular Sequence Data  Nucleic Acid Conformation  Pseudouridine/chemistry/metabolism  RNA, Bacterial/chemistry/metabolism  RNA, Fungal/chemistry/metabolism  RNA, Ile/*chemistry/metabolism  Saccharomyces cerevisiae/*genetics  Structure-Activity Relationship  Substrate Specificity  Support, Non-U.S. Gov't, Transfer, Unité ARN},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Determinant nucleotides of yeast tRNA(Asp) interact directly with aspartyl-tRNA synthetase},

author = {J Rudinger and J D Puglisi and J Putz and D Schatz and F Eckstein and C Florentz and R Giege},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1631068},

isbn = {1631068},

year  = {1992},

date = {1992-01-01},

journal = {Proc Natl Acad Sci U S A},

volume = {89},

number = {13},

pages = {5882-5886},

abstract = {The interaction of wild-type and mutant yeast tRNA(Asp) transcripts with yeast aspartyl-tRNA synthetase (AspRS; EC 6.1.1.12) has been probed by using iodine cleavage of phosphorothioate-substituted transcripts. AspRS protects phosphates in the anticodon (G34, U35), D-stem (U25), and acceptor end (G73) that correspond to determinant nucleotides for aspartylation. This protection, as well as that in anticodon stem (C29, U40, G41) and D-stem (U11 to U13), is consistent with direct interaction of AspRS at these phosphates. Other protection, in the variable loop (G45), D-loop (G18, G19), and T-stem and loop (G53, U54, U55), as well as enhanced reactivity at G37, may result from conformational changes of the transcript upon binding to AspRS. Transcripts mutated at determinant positions showed a loss of phosphate protection in the region of the mutation while maintaining the global protection pattern. The ensemble of results suggests that aspartylation specificity arises from both protein-base and protein-phosphate contacts and that different regions of tRNA(Asp) interact independently with AspRS. A mutant transcript of yeast tRNA(Phe) that contains the set of identity nucleotides for specific aspartylation gave a phosphate protection pattern strikingly similar to that of wild-type tRNA(Asp). This confirms that a small number of nucleotides within a different tRNA sequence context can direct specific interaction with synthetase.},

note = {0027-8424 

Journal Article},

keywords = {Asp/chemistry/*metabolism  Saccharomyces cerevisiae/enzymology  Structure-Activity Relationship  Support, Aspartate-tRNA Ligase/*metabolism  Base Sequence  Binding Sites  DNA Mutational Analysis  Fungal Proteins/metabolism  Molecular Sequence Data  Protein Binding  RNA, FLORENTZ, Fungal/chemistry/metabolism  RNA, Non-U.S. Gov't, Transfer, Unité ARN},

pubstate = {published},

tppubtype = {article}

}