Biologie Digitale de l’ARN

@article{,

title = {Histidylation by yeast HisRS of tRNA or tRNA-like structure relies on residues -1 and 73 but is dependent on the RNA context},

author = {J Rudinger and C Florentz and R Giege},

url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7800496},

isbn = {7800496},

year  = {1994},

date = {1994-01-01},

journal = {Nucleic Acids Res},

volume = {22},

number = {23},

pages = {5031-5037},

abstract = {Residue G-1 and discriminator base C73 are the major histidine identity elements in prokaryotes. Here we evaluate the importance of these two nucleotides in yeast histidine aminoacylation identity. Deletion of G-1 in yeast tRNA(His) transcript leads to a drastic loss of histidylation specificity (about 500-fold). Mutation of discriminator base A73, common to all yeast tRNA(His) species, into G73 has a more moderate but still significant effect with a 22-fold decrease in histidylation specificity. Changes at position 36 in the anticodon loop has negligible effect on histidylation. The role of residues -1 and 73 for specific aminoacylation by yeast HisRS was further investigated by studying the histidylation capacities of seven minihelices derived from the Turnip Yellow Mosaic Virus tRNA-like structure. Changes in the nature of nucleotides -1 and 73 modulate this activity but do not suppress it. The optimal mini-substrate for HisRS presents a G.A mismatch at the position equivalent to residues G-1.A73 in yeast tRNA(His), confirms the importance of this structural feature in yeast histidine identity. The fact that the minisubstrates contain a pseudoknot in which position -1 is mimicked by an internal nucleotide from the pseudoknot highlights further the necessity of a stacking interaction of this position over the amino acid accepting branch of the tRNA during the aminoacylation process. Individual transplantation of G-1 or A73 into yeast tRNA(Asp) transcript improves the histidylation efficiency of the engineered tRNA(Asp). However, a tRNA(Asp) transcript presenting simultaneously both residues G-1 and A73 becomes a less good substrate for HisRS, suggesting the importance of the structural context and/or the presence of antideterminants for an optimal expression of these two identity elements.},

note = {0305-1048 

Journal Article},

keywords = {Anticodon/genetics  Base Sequence  Genes, Asp/genetics  RNA, FLORENTZ, His/*chemistry/*genetics  RNA, Non-U.S. Gov't  Tymovirus/genetics  Yeasts/enzymology, Synthetic/genetics  Histidine-tRNA Ligase/*metabolism  Kinetics  Molecular Sequence Data  *Nucleic Acid Conformation  Point Mutation/physiology  RNA, Transfer, Unité ARN, Viral/metabolism  Support},

pubstate = {published},

tppubtype = {article}

}