evolution connection: ribosomes
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Evolution connection: RibosomesEvolution connection: Ribosomes
Learning goals:Students will understand that 1) some antibiotics work by attacking the ribosome, 2) tiny differences that evolved in the ribosomes of prokaryotes and eukaryotes are responsible for the specificity of those drugs towards bacterial ribosomes, 3) our mitochondria are vulnerable to such drugs because these organelles evolved via endosymbiosis from bacteria, and 4) our evolutionary history matters in our everyday lives.
For the instructor:This short slide set connects the topic of cellular ribosomes to both our evolutionary history and modern medicine. Slide 9 may be skipped to save time. Throughout the notes, optional information is included in parentheses in case the instructor wants to go into more detail. To integrate these slides best, use them immediately after you’ve discussed the structure of ribosomes and their role in the cell. Alternatively, you may wish to use these slides when you discuss translation later in the semester.
Evolution connection: RibosomesEvolution connection: Ribosomes
Ribosomes: An achilles heel for bacteria
Petri dish photo from CDC; researcher photo from CDC/Dr. U.P. Kokko; photo of various medicines from
National Institute of Health
Why don’t antibiotics like streptomycin harm our own cells?
Evolution connection: RibosomesEvolution connection: Ribosomes
Evolution connection: RibosomesEvolution connection: Ribosomes
Ribosomes evolved early in the history of life
All ribosomesshare:
• similar rRNA sequences
• small subunit that decodes mRNA
• large subunit that joins amino acids together
The ribosomeevolved back
here.
Evolution connection: RibosomesEvolution connection: Ribosomes
Ribosomes evolved early in the history of life
The ribosomeevolved back
here.
... and evolvedmodificationsas life’s lineagesdiversified.
Small evolutionary changes big impact
Evolution connection: RibosomesEvolution connection: Ribosomes
Streptomycin-like antibiotics bind to the ribosome
Antibiotic binds here and interferes with protein synthesis …
… but not in eukaryotic ribosomes.
A site antibiotic
ribosome
Evolution connection: RibosomesEvolution connection: Ribosomes
… because ofposition 1408In the small ribosomalsubunit.
Streptomycin-like antibiotics can’t bind to theeukaryotic ribosome …
G A
Evolution connection: RibosomesEvolution connection: Ribosomes
Streptomycin-like antibiotics can’t bind to the eukaryoticribosome …
Images provided by Joseph D. Puglisi.
Evolution connection: RibosomesEvolution connection: Ribosomes
But eukaryotic mitochondrial ribosomes are vulnerable.
G A
Mitochondrion
ribosomes
ReferencesReferences
Bokov, K., and Steinberg, S. V. (2009). A hierarchical model for evolution of 23S ribosomal RNA. Nature. 457: 977-980.
Lynch, S. R., and Puglisi, J. D. (2001). Structural origins of aminoglycoside specificity for prokaryotic ribosomes. Journal of Molecular Biology. 306: 1037-1058.
Pace, N. R. (1997). A molecular view of microbial diversity and the biosphere. Science. 276: 734-740.
Recht, M. I., Douthwaite, S., and Puglisi, J. D. (1999). Basis for prokaryotic specificity of action of aminoglycoside antibiotics. The EMBO Journal. 18: 3133-3138.
Selimoglu, E. (2007). Aminoglycoside-induced ototoxicity. Current Pharmaceutical Design. 13: 119-126.
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