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12 Cards in this Set
- Front
- Back
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Example of ADP-ribosylation of proteins
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EF2 by diptheria toxin
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Example of Phosphorylation of OH groups on proteins
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ser/thr or tyr residues may be phosphorylated; example is eIF2
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Example of acetylation of proteins
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lys residues; example is histones
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Example of carboxylation of proteins posttranslationally
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glu residues; e.g. Vit K-mediated carboxylation of proteins involved in clotting and bone metabolism
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Example of Hydroxylation of proteins prostranslationally
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Pro or Lys; example is collagen
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Example of sulfation of proteins posttranslationally
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Tyr residues; e.g. collagen (PAPS is sulfate donor) phosphoadenylyl sulfate
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Example of posttranslational methylation
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of C-terminus or of side chain N's on lys, arg, and his; e.g. some G-proteins; methyl group donor is SAM
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Example of posttranslational iodination
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certain residues; thyroid hormone addition of lipid moieties (GPI anchor to C-terminus)
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Example of posttranslational ubiquitination
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attachment of ubiquitin peptide to lys; mark for degradation
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Example of posttranslational SUMOlation
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attachment of small ubiquitin-related modifier peptideto lys; can change intracellular location and activity of protein
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Example of posttranslational glycosylation
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most common covalent modification; through O-glycosidic linkages (ser or thr or hydroxylysine (collagen)): i) uses UDP or GDP sugars ii) occurs after protein has reached Golgi (GalNac initial sugar) iii) occurs in cytosol, donation of single sugar
N-glycosidic linkages: amide NH2 on asn i) branched, preassembled oligosaccharide linked to dolichol phosphate (lipid associated with ER membr.) ii) begins in ER through en bloc transfer of oligosaccharide iii) trimming occurs in ER (glc), Golgi (mann), results in common pentasaccharide core (2GlcNac+3 mannose); collagen contains O and N linked sugars; iv) inhibited by tunicamycin functions of glycosylation: i) increase solubility ii) protect against proteolysis iii) influence spatial organization iv) involved in recognition and anitgenicity |
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What are the similarities and differences between prokaryotic and eukaryotic rRNA?
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1) There is only one prokaryotic RNA polymerase and it has fewer subunitsthan pol II
2) Prokaryotic RNA polymerase sigma subunit binds sequence specifically to the Pribnow box at -10 relative to the start of transcription 3) Factors in addition to the RNA polymerase (general transcription factors) are not required 4) Prokaryotic mRNAs are generally NOT post-translationally modified 5) Prokaryotic mRNAs are polycistrionic, i.e. contain the protein coding information for more than one gene-eukaryotic mRNAs are generally monocistrionic 6) Transcription and translation are coupled in prokaryotes (eukaryotes have to process and transport mRNAs before translation) 7) Ribosomes bind sequences specifically to the mRNAs (Shine-Delgarno SD sequence) |
