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Updated: Aug 29, 2025

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity
07:46

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity

Published on: October 8, 2018

7.0K

MiaA (Rv2727c) mediated tRNA isopentenylation of Mycobacterium tuberculosis H37Rv

Smitha Soman1, Siya Ram1,2

  • 1School of Biotechnology, Gautam Buddha University, Gautam Budh Nagar, Greater Noida, Uttar Pradesh, India.

Molecular Biology Research Communications
|September 5, 2022
PubMed

Insights

Transfer RNA (tRNA) modifications enhance protein synthesis accuracy. Researchers identified specific tRNAs targeted by the isopentenyltransferase (MiaA) enzyme in Mycobacterium tuberculosis, confirming its role in essential tRNA modification.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Microbiology

Background:

  • Transfer RNA (tRNA) modifications are crucial for maintaining structural integrity and translational accuracy across all life forms.
  • These modifications, particularly at the anticodon-stem loop (ASL), are vital for stabilizing codon-anticodon interactions, ensuring precise mRNA decoding.
  • In bacteria, tRNA modifications regulate translation in response to environmental stressors, impacting overall physiology.

Purpose of the Study:

  • To investigate the role and substrate specificity of tRNA isopentenyltransferase (MiaA) in Mycobacterium tuberculosis.
  • To identify the specific target tRNAs modified by MiaA in M. tuberculosis strain H37Rv.
  • To confirm the enzymatic activity of recombinant MiaA and its role in the isopentenylation of target tRNAs.

Main Methods:

  • Bioinformatic analysis to identify potential tRNA targets based on the conserved A36A37A38 motif.
  • Purification of recombinant MiaA enzyme from M. tuberculosis H37Rv.
  • In vitro isopentenyltransferase assay using purified MiaA and the substrate DMAPP (dimethylallyl pyrophosphate).

Main Results:

  • The study identified specific tRNA targets for MiaA modification in M. tuberculosis, including tRNALeuCAA, tRNAPheGAA, tRNATrpCCA, and tRNASerCGA.
  • The A36A37A38 sequence motif was confirmed as a key determinant for MiaA substrate recognition.
  • Enzymatic assays validated that recombinant MiaA catalyzes the addition of the isopentenyl group (i6A) to these specific tRNAs.

Conclusions:

  • The isopentenyl modification (i6A) at the A37 position, mediated by MiaA, is a conserved and essential process in Mycobacterium tuberculosis.
  • MiaA plays a critical role in ensuring translational fidelity and potentially regulating bacterial adaptation to environmental conditions.
  • Understanding MiaA's function provides insights into tRNA biology and potential therapeutic targets in M. tuberculosis.
Keywords:
DMAPPIsopentenyl transferaseM. smegmatisMiaATuberculosisi6A

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