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A survey of polypeptide deformylase function throughout the eubacterial lineage
1Unité de Biochimie Cellulaire (CNRS URA 1129), Institut Pasteur, Paris, France.
Journal of Molecular Biology
|March 14, 1997
Summary
N-terminal formylation, a key bacterial trait, is ancient. Studying deformylase (def) genes in various bacteria confirms its evolutionary significance and conserved nature across species.
Area of Science:
- Molecular Biology
- Evolutionary Biology
- Genetics
Background:
- N-terminal formylation of polypeptides is a conserved feature distinguishing eubacteria.
- The evolutionary origin of this trait remains a key question in understanding bacterial lineage.
Purpose of the Study:
- To investigate the ancientness of N-terminal formylation in eubacteria.
- To characterize def genes encoding polypeptide deformylase in diverse bacterial species.
Main Methods:
- Systematic genome sequence analysis and genetic screening were employed.
- Conditional viability of Escherichia coli def mutants was utilized.
- Eight polypeptide deformylase sequences were obtained from Lactococcus lactis, Bacillus subtilis, Calothrix PCC7601, and Thermotoga maritima.
Main Results:
- A highly homologous family of polypeptide deformylase sequences was identified.
- The fmt gene, encoding Met-tRNAi formyltransferase, was found downstream of the def gene in most species.
- Amino acid composition variations in def- and fmt-encoded proteins correlate with genome nucleotide composition.
Conclusions:
- The findings strongly support the ancestral nature of N-terminal formylation in eubacteria.
- Species of origin are more discernible from amino acid composition than function.
- The study highlights the deep evolutionary roots of a fundamental bacterial process.