Lecture 11: Functions and Dysfuction of Protein Processing Flashcards
Streptomycin
- prokaryotic 30s subunit binding
- interferes w/fmet-tRNA bindings and 50s association
Clindamycin and erythromycin
- prokaryotic 50s subunit binding
- blocks translocation of ribosome
Tetracycline
- prokaryotic 30s subunit binding
- blocks aminoacyl-tRNA to ribosomal complex
- blocks ELONGATION
Chloramphenicol
- prokaryotic inhibitor
- inhibits peptidyl transferase, impairs peptide bond formation
Shiga toxin and Ricin
- eukaryotic 60s subunit binding
- blocks aminoacyl-tRNA
Diphtheria toxin
- eukaryotic inhibitor
- inactivates GTP-bound EF-2
- blocks ribosomal translocation
Cycloheximide
- eukaryotic inhibitor
- inhibits peptidyl transferase
- impairs peptide bond formation
Puromycin
- eukaryotic/prokaryotic
- causes premature chain termination
- enters A site, forms puromycylated (premature chain release)
- hydrolysis resistant (stops ribosome function)
Silent Mutations, Missense Mutations, Nonsense Mutations, Frameshift Mutations
Silent - does not change amino acid
Missense - changes amino acid in protein (no effect or vastly different effect)
Nonsense - codon changes into stop codon (truncated)
Frameshift - OOF (change codon sequence, alteration in AA sequence of protein)
Sickle Cell Anemia
- missense (6th codon in allele of Beta-globin)
- glutamic acid changed to valine (hydrophilic to hydrophobic)
- poor oxygen capacity and tend to clog capillaries (deformed RBCs)
Duchenne Muscular Dystrophy
- frameshift (dystrophin gene deletions)
- little (Becker) or no (Duchenne) dystrophin protein
- muscle wasting
Cytoplasmic and Secretory proteins go where?
Cytoplasmic: cytosol, mitochondria, nucleus, peroxisomes (begin/end on free ribosome)
Secretory: ER, lysosomes, plasma membranes, secretion (begins free ribosome, sent to ER)
Mitochondria Translocation Signal
N-terminal hydrophobic alpha-helix signal peptide
Nucleus Translocation Signal
Lysine/Arginine rich (KKKRK)
Peroxisome Translocation Signal
Serine/Lysine/Leucine (SKL)