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39 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Prokaryotic Ribosomal Units
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30s
50s become 70s |
30s- 16s rRNA
50s- 25 5S rRNA |
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Eukaryotic ribosomal units
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40S
60S 80S |
40S 30 18S
60S 45 28S 5.8S 5S |
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tRNA
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AA attached to 3' end
64 codons 61 and 3 stop methionine starts stop codons? |
UAA UAG UGA
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Aminoacyl-tRNA synthetase
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catalyzes the covalent link of AA to tRNA
specificity insured by anticodon ATP |
ATP and AA be AAacyl to AMP
AAacyl AMP becomes AAacyl tRNA and AMP |
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Prokaryotic initiation
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fMet transformylase
intiation factors IF-1,2,3 make pre initiation complex with fMet, mRNA, GTP anticodon binds to AUG via H bonding called shine delgarno 16SrRNA and 30S |
GTP hydrolyzed to GDP
IF released 50S joins tadah! fMET at P site of 70S |
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Eukaryotic initiation
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no FMet
Met GTP eIF-2 ternary complex this binds to 40S subunit eIF-4F binds to CAP site at 5' end of mRNA brings eIF-4a,b forms preintiation complex |
complex moves along 5'UTR until first AUG
GTP hydrolyzed eIFs leave, 60S joins 80s formed Met in P site eIF-2 GDP goes back to GTP via eIF-2B |
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Reg at Initiation
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Hemin
Inerferon Insulin |
Hemin Interferon affect eIF-2
insulin eIF-4e |
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Hemin mech
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targets intiation step of eukaryotes
iron is toxic because of superoxide ions radicals iron key for heme groups co factor for ribonucleotide reductase |
Low heme phozs eIF-2 kinase, which phozs eIF-2 which inactivates it
clinical iron deficiency leads to anemia. fatigue. no beath, headache, dizzy, infection, arrythmia |
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Interferon effect
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phozs eIF-2
activated endonuclease that destroys mRNA |
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Leukoencephalopathy
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VanishingWhiteMatter
childhood ataxia with central hypomyelination disease |
mutations in subunit eIF-2B
gait difficulties optic atrophy white matter replaced with CSF and water |
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Insulin effect
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eIF-4E
insulin removes eIF-4E binding protein from eIF4E. activates a serine protein kinase that causes this dissociation. |
now free to bind to mRNA cap
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prokaryotic elongation
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EF-tu (EF-1 in eu)
EF-G (EF-2 in eu) |
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eukaryotic elongation
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EF-1alpha brings next tRNA to A site
GTP hydrolyzed EF 1 leaves peptide bond forms betwen C of first and N of second AA. catalyzed by peptidyl transferase |
EF-2-GTp translocates it from A to P
ribsome moves over empty tRNA moves to E site GTP hydrolyzed and EF2 GTP leaves |
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E/Pro Dif
Binding of mRNA |
E- Cap at 5' end binds to eIF and 40S
scanning for AUG P- Shine Delgarno upstream of AUG binds to comp sequence 16S |
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E/P dif
First amino acid |
E- methinonine
P- formyl- methionine |
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E/P
intitation factors |
E- eIFs
P- IFs |
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E/P
ribosomes |
E-80s (40/60)
P- 70S (30/50) |
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E/P
elongation factor first |
E- EF1alpha
P-EF-Tu |
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E/P
factors involving regeneration of EF |
E- EF-beta gamma
P- EF-Ts |
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E/P
second elongation factor |
E- EF2
P- EFg |
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Termination
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Stop codon no tRNA
release factor eRF binds to A eRF converts peptidyl transferase into cleavage enzyme |
cleaves aminoacyl bond between last AA and tRNA at P site
gtp hydrolyzed protein released ribsome dissociates |
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Inhibitors of Protein Biosynthesis
mech(3) |
Streptomycin
Puromycin Diptheria |
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Cycloheximide
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Elongation
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Eukaryotes
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Erythromycin
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translocation
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prokaryotes
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Neomycins
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translaton
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prokaryotes
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Puromycin
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Peptide transfer
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pro and eukaryotes
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Ricin
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translation
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eukaryotes
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streptomycin
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initiation, elongation
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prokaryotes
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tetracyclins
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AA-tRNA binding
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pro and eukaryotes
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Streptomycin Mech
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similar to Fmet acts as a competitive inhibitior in prokaryotes for binding with the ribosome
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Puromycin mech
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resembles 3' end of tyrosyl tRNA. reactive amino group forms between this and peptidyl tRNA at P site. High enough concentrations can compete at A site.
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kink in chain
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Diptheria mech
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bacterium corynebacterium diphtheriae which has an enzyme that catlayzes the reaction to link ADP to EF-2
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nonreversible competition
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Protein Targeting A-J
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A- Proteins destined for wherever contain signal peptide sequence at N terminus
B- SRP (signal recognition particle) sees the delivery sequence C-SRP will direct ribosome to ER and interacts with docking protein D-Protein enters ER lumen E- Signal peptide removed. NOTE proteins differ from gene template F-inside ER protein packaged with secretory vesicle and sent to golgi G- protein modification H-Secretory proteins leave I- membrane proteins stay on membrane J- lysosomal targeting with mannose 6 phospate |
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I cell disease (also called mucolipidosis III)
mech |
Deficiency in GlcNAC-1-P transferase which causes mannose 6 phosphate to be absent
lysosomal proteins not delivered secreted instead inclusion bodies ( I cells) build up |
severe psychomotor retardation and death by 10 yo
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Post translational modifications
A_D |
A- amino acid side groups
B- protein folding C- Processing of proteins D- Secretion of proteins |
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Amino acid side group mods
1-7 |
1- Acetylation of histones APL
2- Carboxyglutamation 3-Glycosylation 4- Hydroxylation 5- Methylation 6- Phosphorylation 7- Prenylation |
Carboxy deals with modifying clotting proteins prothrombin factor X
conversion of glutamic acid so that it can bind to calcium and clot Glycosylation deficiency causes CF. CFTR not glycosylated due to three nucleotide deletion of phenylalanine 508-fails to fold properly hydroxylation targets proline lysine in collagen to stabilize prenyl group anchors protein to cell membrane |
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Protein folding clinical
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Mad cow (creutzfeldt jacob)
Alzheimers Huntingtons |
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Protein processing
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1disulfide bond formation between cysteine residues
2- cleavage of precursor protein to generate shorter one (prepro insulin) |
familial hypoinsulinemia have half insulin have proinsulin- half way between normal and diabetic
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Secretion
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insulin in response to serum glucose
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