Molecular Evidence for the Ancient Origin of the Ribosomal Protection Protein That Mediates Tetracycline Resistance in Bacteria
- 285 Downloads
The ribosomal protection proteins (RPPs) mediate the resistance to tetracycline (TC) in Gram-positive and Gram-negative bacteria. The RPPs display sequence similarity to translation elongation factors, EF-G/EF-2 and EF-Tu/EF-1α. To determine the evolutionary origin of the RPPs, we constructed a composite phylogenetic tree of the RPPs, EF-G/EF-2 and EF-Tu/EF-1α. This tree includes two universal trees for the EF-G/EF-2 and EF-Tu/EF-1α, which form clusters corresponding to the respective two groups of proteins from three superkingdoms. The cluster of RPPs was placed at a point between the EF-G/EF-2 and EF-Tu/EF-1α clusters. The branch length (substitutions/site) between the node for the RPP cluster and the primary divergence of the RPPs was statistically shorter than that between the node for this cluster and the primary divergence in the EF-G/EF-2 cluster. This indicates that the RPPs derived through duplication and divergence of the ancient GTPase before the divergence of the three superkingdoms. Furthermore, this suggests the RPPs’ extant function occurred before the streptomycetes that include the TC-producing strains. Therefore, the RPPs evolved independent of the presence of TCs and serve a function other than antibiotic resistance. The RPPs may provide ribosomal protection against other chemical substances in the environment.
KeywordsBacteria Antibiotic Tetracycline Resistance Ribosomal protection protein Evolution Origin EF-G/EF-2 EF-Tu/EF-1α Composite phylogenetic tree
We thank Ms. Annie Marlow for proofreading the manuscript. This work was supported by the 21st Century COE Program from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT); by a Sasagawa Scientific Research Grant from The Japan Science Society; and by the Mitsubishi Foundation from the Mitsubishi Group.
- Adachi J, Hasegawa M (1996) MOLPHY version 2.3: Programs for molecular phylogenetics based on maximum likelihood. Comput Sci Monogr Inst Stat Math 28:1–150Google Scholar
- Benveniste R, Davies J (1973) Aminoglycoside antibiotic-inactivation enzymes in actinomycetes similar to those present in clinical isolates of antibiotic resistant bacteria. Proc Natl Acad Sci U S A 172:3628–3632Google Scholar
- Zuckerkandl E, Pauling L (1965) Evolutionary divergence and convergence in proteins. In Bryson V, Vogel HJ (eds) Evolving genes and proteins. Acadmic Press, New York, pp 97–166Google Scholar