Recognition of G-1:C73 atomic groups by Escherichia coli histidyl-tRNA synthetase

J Am Chem Soc. 2004 Jan 14;126(1):64-5. doi: 10.1021/ja0381609.


This work focuses on the RNA-protein interactions necessary for efficient aminoacylation of tRNAHis by Escherichia coli histidyl-tRNA synthetase (HisRS). The E. coli tRNAHis acceptor stem is characterized by a unique "extra" G-1:C73 base pair. Previous in vivo and in vitro studies showed that G-1:C73 is a major recognition element for E. coli HisRS. To further probe the role of the G-1:C73 base pair in specific aminoacylation, we carried out atomic group "mutagenesis" studies. Systematic base analogue substitutions at the -1:73 position of chemically synthesized microhelixHis substrates suggest that the G-1 base serves to position the 5'-monophosphate, which is critical for aminoacylation. Additionally, the C73 and G-1 bases contain major groove exocyclic atomic groups that contribute to HisRS recognition.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Pairing
  • Escherichia coli / enzymology*
  • Histidine-tRNA Ligase / chemistry*
  • Histidine-tRNA Ligase / metabolism*
  • Nucleic Acid Conformation
  • RNA, Transfer, Amino Acyl / chemistry*
  • RNA, Transfer, Amino Acyl / metabolism*
  • Substrate Specificity


  • RNA, Transfer, Amino Acyl
  • Histidine-tRNA Ligase