Translation in Prokaryotes and Eukaryotes

Translation

process of reading the information in messenger RNA (mRNA) to create a protein

genetic code

Sequence of nucleotide bases in a gene, which specifies the sequence of amino acids in a protein

Codon

sequence of three nucleotides in messenger RNA (mRNA) that specifies a particular amino acid

Degenerate:

Most amino acids

encoded by more than one codon

methionine and tryptophan

what amino acids only have one codon

cytoplasm for both pro and euk

where does translation occur

mRNA

ribosomal subunits

tRNA

GTP

soluble proteins aka intiation factors

what is required for translation initiation

30s and 50s (70s)

ribosomal subunits for prokaryotes

60s and 40s (80s)

ribosomal subunits for eukaryotes

formulated methionine

what type of tRNA does does prokaryotes have in initiation

A site

Acceptor site or attachment site for incoming aminoacyl-tRNA

P site

Peptidyl site - occupied by peptidyl-tRNA, tRNA carrying the growing polypeptide

chain

E site

Empty tRNA (unloaded or deacylated tRNA) occupies prior to exiting the ribosome

aminoacyl-tRNA

A tRNA with an amino acid attached.

Shine Dalgarno sequences

marks the start of each coding sequence,

letting the small ribosomal subunit find the right start codon for each gene for prokaryotes

eIF-4 (Eukaryotic Initiation factor)

binds the 5'cap of mRNA and helps to bind the 40S (small ribosomal subunit) correctly. - eukaryotes

5' is phosphorylated and is the shorter side.

3' is the attachment site for amino acid site on the CCA group

for tRNA, how to tell difference between 5' and 3'

methionyl formyl transferase

what enzyme converts non formyl methylates to forymlated

initiator factors that either bind to initiator tRNA or the small ribosomal subunit

what are the soluble proteins functions

(e) IF2GTP

initiator factor that bound to tRNAs

IF-1 and IF-3 (prokaryotes)

eIF1, eIF1A, eIF3, eIF5

initiator factor that bound to subunit

Hydrolysis of GTP to GDP provides energy for the assembly of initiation complex

Initiator factors

(IFs) bound to initiator tRNA function

IFs bound to small ribosomal subunit

facilitates the binding of small subunit to initiator tRNA and base pairing between anticodon and codon

Small subunit bound to IFs

what scans for the Shine Dalgarno sequence

Conversion of GTP to GDP

what helps bind the large subunit

Initiator tRNA

what is the only tRNA that bind to P site

Amino Acid is attached on the tRNA

when are tRNA's considered charge

Aminoacyl-tRNA synthetases

what activates the amino acid for transfer to peptide

adenylation and transfer of aminoacyl group

what are the two steps of activation of

-amino acid + ATP-> aminoacyl-AMP + PPi

adenylation step

aminocyl-tRNA synthetases

what enzyme is used in adenylation step

amino-acyl AMP + tRNA -> aminoacyl-tRNA + AMP

activation of aminoacyl group

one enzyme for each amino acid, have high discriminating activation sites , and proofreads

properties of aminoacyl-tRNA syntheses

attach carboxyl of their target amino acid of the 2'OH of terminal adenosine

Class I of aminoacyl-tRNA syntheses

attach the carboxyl of their target amino acid to the 3' OH of adenosine

Class II of aminoacyl-tRNA syntheses

small ribosome binds to the initiation factors which then binds to the 5' cap

how is the pre-initiation complex formed for eukaryotes

GTP is releases to for GDP - large ribosomal subunit joins with the help of eIF2

what is attached when the complete initiation complex of eukaryotes is formed

RF1 and RF2

termination release factors for prokaryotes

eRF

termination release factors for eukaryotes

helps attach amincoacyl tRNA onto A site

what is the overall role of initiation factors

helps make peptide bond and translocation of tRNAs

what is the overall role of elongation factors

complex dissociation of nascent protein

when the release factors bind to A what happens