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Idiosyncratic features in tRNAs participating in bacterial cell wall synthesis
Régis Villet1, Matthieu Fonvielle, Patricia Busca
1INSERM, U872, LRMA, Centre de Recherche des Cordeliers, Pôle 4, Equipe 12, Paris, F-75006, France.
Nucleic Acids Research
|October 13, 2007
Summary
The FemX enzyme in Weissella viridescens is crucial for peptidoglycan synthesis and a potential antibiotic target. Its high specificity for l-alanine transfer relies on tRNA acceptor stem recognition, offering a novel approach for drug design.
Area of Science:
- Microbiology
- Biochemistry
- Structural Biology
Background:
- Peptidoglycan synthesis is essential for bacterial cell wall integrity.
- The FemX enzyme from Weissella viridescens plays a key role in synthesizing peptidoglycan precursors.
- FemX is a promising target for novel antibiotic development due to its essential function.
Purpose of the Study:
- To investigate the substrate specificity of the FemX(Wv) aminoacyl transferase.
- To identify the molecular determinants governing FemX(Wv) recognition of Ala-tRNA(Ala).
- To explore the potential for designing specific FemX(Wv) inhibitors.
Main Methods:
- Extensive analysis of peptidoglycan structure in Weissella viridescens.
- Comparison of natural and in vitro-transcribed tRNAs.
- Site-directed mutagenesis of tRNA(Ala) and FemX(Wv).
- Modeling of tRNA(Ala) within the enzyme's catalytic cavity.
Main Results:
- FemX(Wv) exhibits high specificity for incorporating l-alanine.
- Enzyme specificity is primarily determined by the tRNA sequence, particularly the acceptor stem.
- Cytosine bases in the G1-C72 and G2-C71 base pairs are critical for FemX(Wv) activity.
- The G3-U70 wobble base pair, a key determinant for alanyl-tRNA synthetase, is non-essential for FemX(Wv).
Conclusions:
- FemX(Wv) recognition of tRNA(Ala) differs significantly from that of alanyl-tRNA synthetase.
- Targeting the distal portion of tRNA(Ala) offers a strategy for developing specific FemX(Wv) inhibitors.
- This research provides a foundation for designing novel antibiotics that disrupt peptidoglycan synthesis.
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