首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Conformation effects of base modification on the anticodon stem-loop of Bacillus subtilis tRNA(Tyr)
Authors:Denmon Andria P  Wang Jiachen  Nikonowicz Edward P
Institution:
  • Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251-1892, USA
  • Abstract:tRNA molecules contain 93 chemically unique nucleotide base modifications that expand the chemical and biophysical diversity of RNA and contribute to the overall fitness of the cell. Nucleotide modifications of tRNA confer fidelity and efficiency to translation and are important in tRNA-dependent RNA-mediated regulatory processes. The three-dimensional structure of the anticodon is crucial to tRNA-mRNA specificity, and the diverse modifications of nucleotide bases in the anticodon region modulate this specificity. We have determined the solution structures and thermodynamic properties of Bacillus subtilis tRNATyr anticodon arms containing the natural base modifications N6-dimethylallyl adenine (i6A37) and pseudouridine (ψ39). UV melting and differential scanning calorimetry indicate that the modifications stabilize the stem and may enhance base stacking in the loop. The i6A37 modification disrupts the hydrogen bond network of the unmodified anticodon loop including a C32-A38+ base pair and an A37-U33 base-base interaction. Although the i6A37 modification increases the dynamic nature of the loop nucleotides, metal ion coordination reestablishes conformational homogeneity. Interestingly, the i6A37 modification and Mg2+ are sufficient to promote the U-turn fold of the anticodon loop of Escherichia coli tRNAPhe, but these elements do not result in this signature feature of the anticodon loop in tRNATyr.
    Keywords:DMAPP  dimethylallyl diphosphate  ASL  anticodon stem-loop  5&prime  -NTP  5&prime  nucleoside triphosphate  NOE  nuclear Overhauser enhancement  NOESY  NOE spectroscopy  DQF  double quantum filtered  2D  two-dimensional  3D  three-dimensional  HetCor  heteronuclear correlation  HSQC  heteronuclear single quantum coherence  rMD  restrained molecular dynamics  DSC  differential scanning calorimetry  COSY  correlated spectroscopy  TOCSY  total COSY  t6A37  N6-threonylcarbamoyl-A37  EDTA  ethylenediaminetetraacetic acid  PDB  Protein Data Bank
    本文献已被 ScienceDirect PubMed 等数据库收录!
    设为首页 | 免责声明 | 关于勤云 | 加入收藏

    Copyright©北京勤云科技发展有限公司  京ICP备09084417号