Histidylation by yeast HisRS of tRNA or tRNA-like structure relies on residues -1 and 73 but is dependent on the RNA context - PubMed (original) (raw)

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

J Rudinger et al. Nucleic Acids Res. 1994.

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.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Science. 1989 Mar 10;243(4896):1363-6 - PubMed
    1. Virology. 1988 Nov;167(1):201-6 - PubMed
    1. Science. 1989 Dec 1;246(4934):1135-42 - PubMed
    1. J Biomol Struct Dyn. 1987 Apr;4(5):707-28 - PubMed
    1. Nature. 1990 Apr 19;344(6268):787-9 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources