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Inteins invading mycobacterial RecA proteins
I Saves1, M A Lanéelle, M Daffé
1Institut de Pharmacologie et Biologie Structurale UMR5089, CNRS Université Paul Sabatier Toulouse III, Toulouse, France. saves@ipbs.fr
Abstract:
Five new inteins were discovered in a survey of 39 mycobacterial strains that was undertaken to clarify the role of RecA inteins in mycobacteria. They are all inserted at the RecA-b site of the recA gene of Mycobacterium chitae, 4. fallax, M. gastri, M. shimodei and M. thermoresistibile and belong to the MleRecA allelic family. Sequence analysis showed that although only M. tuberculosis harbours an intein at the RecA-a site the sequence of the RecA-b site is well conserved between species. Furthermore, the presence of inteins does not correlate with specific characteristics of the species such as pathogenicity or growth rate.
Insights
Five new RecA inteins were found in mycobacteria, inserted at the RecA-b site. Their presence doesn't link to pathogenicity or growth rates in these bacterial species.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- RecA proteins are crucial for DNA repair and recombination in bacteria.
- Inteins are protein segments that excise themselves from precursor proteins.
- The role of inteins in mycobacteria, particularly at the RecA locus, requires further investigation.
Purpose of the Study:
- To identify and characterize novel inteins within the RecA gene of various mycobacterial strains.
- To understand the distribution and allelic family of RecA inteins in mycobacteria.
- To investigate potential correlations between RecA intein presence and species-specific characteristics.
Main Methods:
- Bioinformatic survey of the recA gene in 39 mycobacterial strains.
- Sequence analysis of identified inteins and their insertion sites.
- Comparative analysis of RecA intein sequences across different species.
Main Results:
- Discovery of five new inteins in Mycobacterium chitae, M. fallax, M. gastri, M. shimodei, and M. thermoresistibile.
- All identified inteins were located at the RecA-b insertion site and belonged to the MleRecA allelic family.
- The RecA-b site sequence is conserved across species, while the RecA-a site intein is unique to M. tuberculosis.
- No correlation was found between intein presence and pathogenicity or growth rate.
Conclusions:
- The RecA-b site is a common intein insertion point in diverse mycobacteria.
- RecA inteins in mycobacteria represent a conserved allelic family.
- Intein occurrence at the RecA-b site is independent of key mycobacterial species characteristics.