Inhibitors of Protein Synthesis Flashcards
T/F. Protein synthesis inhibitors work by direct synthesis inhibition or decreased fidelity in reading the genetic code.
True, there is still much controversy about specific mechanisms
Which drug binds to proteins in interface between 30S and 50S or bind to each separately?
aminoglycosides
Which aminoglycoside only binds to 30S?
streptomycin
What effects do aminoglycosides have after bind to ribosomes?
- interfere with tRNA attachment
- block activity of initiation complex
- distortion of mRNA triplet codon leading to mispairing between codon and aminoacyl tRNA anticodon (misreading). Associated with ribosomal protein L6
- polysome breakdown to monosomes which are stabilized (streptomycin)
___ bind 30S and block binding of tRNA to mRNA at the ___ site.
Tetracyclines; A
How does Chloramphenicol work?
binds to 50S ribosome and inhibits peptidyl transferase by preventing attachment of amino acid end of aminoacyl-tRNA to the “A” site
___ binds to the 50S ribosome at the same site as Chloramphenicol and can be displaced by it.
Clindamycin
What is the mechanism of erythromycin (macrolides)?
binds to 50S close to clindamycin and chloramphenicol sites.
inhibits translocation and causes release of oligo-peptidyl tRNA
___ binds the 50S ribosome and stimulates dissociation of the peptidyl-tRNA.
Quinupristin
___ binds the 50S ribosome and prevents binding of aa-tRNA to the ___ site.
Dalfopristin; acceptor
What protein synthesis inhibitors are only used in combination?
Quinupristin/Dalfopristin
___ binds the ___S ribosome and blocks formation of the initiation complex.
Linezolid; 50
What ribosome is found in bacteria?
70S (50S large subunit + 30S small subunit)
Which protein synthesis inhibitors have bacteriCIDAL actions? Of these two, which ribosome do they bind?
- Aminoglycosides (30S/50S)
2. Quinupristin/Dalfopristin (50S)
Which protein synthesis inhibitor only binds the 30S ribosomal subunit?
tetracyclines
