Translation

Dr.KevinAhern

CentralDogma

mRNAStructure

Bacteria

GeneticCode

Universal Redundant Logical Punctuated

64 Codons 3 Stops 1 Start 2 Unique for AA 59 Redundant

TranslationSteps

CentralDogma

Eukaryotes

Nucleus

Cytoplasm

Translation

SimpleViewofTranslation

Start Codon Stop Codon

Structure

tRNAs-TranslatorMolecules

Amino Acid Attachment Point

tRNAs-TranslatorMolecules

AminoAcidActivation-ChargingoftRNAs

Aminoacyl tRNA-synthetase

Type 1 - AA on 2’ OH Type 2 - AA on 3’ OH

“Charging”oftRNAs

fMetSynthesisinProkaryotes

WobbleBase

WobbleBase

SmallRibosomalSubunit(30SProkaryotes)

LargeRibosomalSubunit(50SProkaryotes)

Structure

50S Ribosomal Subunit

rRNAs

SimpleOverview

Overview

Prokaryotes-Shine-DalgarnoSequence

Shine-DalgarnoSequence

16S rRNA Sequence

Initiation

Initiation

Structure

EF-Tu

Protection Against Hydrolysis

Elongation

Elongation

Termination

1.BindingofmRNAbysmallsubunit2.Slidingtoidentifystartcodon(Shine-Dalgarno)3.BasepairingofanticodonofinitiatortRNAtoAUGinmRNA(3IFs)4.Bindingoflargesubunit5.EntryofsecondtRNAintoA-site(EF-Tu)6.Peptidebondformation-peptideontRNAinA-site7.Translocation(requiresGTP&EFG)8.ExitofusedtRNA,entryofnewchargedtRNA9.Repeat5-8toSTOPCodon10.Entryofreleasefactorwithwater

TranslationinProkaryotes

TranslationinEukaryotes

Differences 1. mRNA structure 2. Ribosome sizes (60S & 40S) 3. rRNA sizes (extra rRNA) 4. No Shine-Dalgarno 5. No fMet

TranslationinEukaryotes-Initiation

Kozak Sequences

EukaryoticTranslation

Elongation

EukaryoticTranslation

Bonding to mRNA

Premature Stopping of Translation

Degradation of mRNA

MembraneProteins

Structure

MembraneProteinSynthesis