1. 1
TRANSLATION

2. 2 TRANSLATION INTRODUCTION
Protein (amino acid polymer, N terminus, C terminus
Ribosomes: 30 S subunit plus 50 S subunit form functional 70 S ribosome
mRNA is read 5' to 3'
Initiation Codons; Stop Codons
Polysomes
INITIATION
Initiator tRNA (N - formyl methionyl tRNA)
Initiation complex
ELONGATION
Peptidyl transferase
A, P, E sites on ribosome
TERMINATION
Stop codons
SHINE-DALGARNO

3. AMIDES 3 PEPTIDE BOND AMINE ACID AMIDE MONO SUBSTITUTED DISUBSTITUTED
PEPTIDE-AMIDE FORMED BETWEEN TWO AMINO ACIDS: ALANYL-GLYCINE
PEPTIDE BOND

4. [STOP CODONS = UAA/UAG/UGA]4
PROMOTER +1
GENE 5' 3' 3' 5'
TRANSCRIPTION 5' 3'
UNTRANSLATED REGION
TRANSLATION N C
CODE
NOBEL
HOLLEY
NIRENBERG
KHORANA
[STOP CODONS = UAA/UAG/UGA]

5. RIBOSOMES - NON-SPECIFIC5
RIBOSOMES - NON-SPECIFIC
TRANSLATE ANY MESSAGE
PROKARYOTIC
70S S S
SUBUNITS
COMPOSITION
50S
30S
NUMBER OF DIFFERENT PROTEINS 34 21
NUMBER OF DIFFERENT rRNA MOLECULES
ONE - 5S
ONE - 23S
ONE 16S
POLYSOMES

6. EACH SPECIFIC FOR 1 AMINO ACID AND 1 CODON6
TRANSFER RNA tRNA ~ 60
EACH SPECIFIC FOR 1 AMINO ACID AND 1 CODON HO 3' 5'
tRNAPHE
SPECIFIC FOR
PHENYLALANINE 3' 5'
ANTICODON 5' 3'
mRNA
CODON FOR PHENYLALANINE
tRNA - IS AN ADAPTER - ADAPTS AMINO ACID AND CODON

7. AMINO ACID + ATP + tRNA AMINO ACYL-tRNA + AMP + PPi8
OVERALL:
AMINO ACID + ATP + tRNA AMINO ACYL-tRNA + AMP + PPi
STEP 1: +
NUCLEOTIDYL
TRANSFER
ANHYDRIDE
PPi
AMINO ACID + ATP AMINO ACYL-AMP + PPi
AMINO ACID ACTIVATING ENZYME =
AMINO ACYL~tRNA SYNTHETASE

8. STEP 2: AMINO ACYL AMP + tRNA AMINO ACYL~tRNA + AMP9
STEP 2: AMINO ACYL AMP + tRNA AMINO ACYL~tRNA + AMP
AMINO ACYL~AMP
3' END
tRNA
AMINO
ACYL~tRNA
AMP

9. A THREONINE tRNA WITH AN ANTI-CODON OF7
GENETIC CODE IS DEGENERATE -
DIFFERENT TRIPLETS ENCODE THE SAME AMINO ACID
ACA
ACG
ACC
ACU
ALL CODE THREONINE
"WOBBLE" MEANS THAT SOME SPECIFIC tRNAs CAN READ MORE THAN ONE CODON
A THREONINE tRNA WITH AN ANTI-CODON OF
3' UGG 5'
5' ACC 3'
5' ACU 3'
PAIRS WITH OR
THREONINE
"WOBBLE" MAKES IT POSSIBLE FOR AN ORGANISM TO TRANSLATE ALL 61 CODONS WITH FEWER THAN 61 tRNAs
PROKARYOTES OFTEN HAVE tRNAs
SOME DIFFERENT tRNAs CARRY THE SAME AMINO ACIDS
SOME HIGHLY SPECIALIZED PROKARYOTES HAVE ~ 40
tRNA GENES

10. INITIATING TRANSLATION9
INITIATING TRANSLATION
FORMYL METHIONINE~tRNA
[SPECIFIC FOR STARTING TRANSLATION]
METHIONINE + tRNAfMET
+ ATP
+ ACTIVATING ENZYME
fMET
fMET
FORMYL
GROUP
[FOLIC ACID]
N-FORMYL METHIONYL
~tRNAfMET
METHIONYL
tRNAfMET

11. INITIATION COMPLEXES 10 mRNA + 30S + F - MET~tRNAfMET
+ GTP + INITIATION PROTEINS
F MET
30S INITIATION COMPLEX
30S SUBUNIT 5'
pppG
mRNA 3'
F MET
50S SUBUNIT
70S RIBOSOME 3'
pppG E P A
EXIT
ACCEPTOR
PEPTIDYL

12. ELONGATION-POLYMERIZATION11
ELONGATION-POLYMERIZATION
F-MET
SER
5' G 3' P A
F-MET
SER
TYR
5' G 3' P A
PEPTIDYL TRANSFERASE
[CHLORAMPHENICOL]

13. 12 5' 3' P A TRANSLOCATION [ERYTHROMYCIN – INHIBITS MOVEMENT
F-MET HO
SER
TYR 5' 3' P A
TRANSLOCATION [ERYTHROMYCIN –
INHIBITS MOVEMENT
AMINO ACYL TRNA
FROM A SITE TO P SITE, BLOCKS
ELONGATION;
AZITHROMYCIN]
F-MET HO
SER
TYR 5' 3' E P A

14. GUC 13 HO GLN F-MET SER HO TYR 5' E A P
TETRACYCLINE – INHIBITS AMINO ACYL TRNA BINDING A SITE
DOXYCYCLINE - NEWER
STREPTOMYCIN - TRNA MISMATCHING, MIS-TRANSLATION SPECTINOMYCIN - BINDS 30S SUBUNIT; EXACT MECHANISM ?
ALL INHIBIT 30S RIBOSOME FUNCTION

15. PEPTIDYL TRANSFERASE PEPTIDYL TRANSFERASE UN-CHARGED tRNA14
PEPTIDYL
TRANSFERASE
UN-CHARGED
tRNA
PEPTIDYL ~ tRNA

16. AUG AUG UAA HOW DO RIBOSOMES KNOW WHERE TO START TRANSLATING? AUG AUG15
HOW DO RIBOSOMES KNOW WHERE TO START TRANSLATING?
A. HOW TO DISTINGUISH INITIAL AUG FROM INTERNAL AUG
AUG
AUG
UAA 5' 3'
PROTEIN CODING REGION
UNTRANSLATED
REGION
INTERNAL AUG
B. HOW TO RECOGNIZE SEVERAL INITIATING AUG's IN ONE mRNA
AUG
AUG
AUG 5' 3'
1st CODING
REGION
2nd CODING
REGION
3rd CODING
REGION
POLY CISTRONIC mRNA RIBOSOMES TRANSLATE ALL THREE INDEPENDENTLY. HOW?

17. SHINE DALGARNO SEQUENCES:16
SHINE DALGARNO
SHINE DALGARNO
AUG
AUG 5' 3'
CODING REGION
CODING REGION
PROTEIN CODING REGIONS ARE PRECEDED BY SHINE-DALGARNO SEQUENCES [PROKARYOTES]
SHINE DALGARNO SEQUENCES:
~ 7 +1 5'
SHINE
DALGARNO

18. 17
BINDING BETWEEN SHINE-DALGARNO AND rRNA (16S) POSITIONS mRNA SO THAT AUG OCCUPIES P SITE
30S SUBUNIT
SITES

19. 18
REPLICATION, TRANSCRIPTION & TRANSLATION - DYNAMIC
mRNA
RIBOSOMES
PROTEINS
THEY ALL
GO ON AT
THE SAME
TIME !

20. RIBOSOMES ARE RIBOZYMES -
THE ACTIVE SITE FOR CATALYZING PEPTIDE BOND FORMATION IS ENTIRELY RNA
23S rRNA IS PEPTIDYL TRANSFERASE
ADENINE [#2451] PARTICIPATES IN FORMING PEPTIDE BONDS 19
CHLORAMPHENICOL
BINDS A 2451 &
A INHIBITS
ADENINE #2451
APPRECIATE !
H BOND
ADENINE N3 TAKES PROTON
NITROGEN ATTACKS

21. 20 APPRECIATE ! tRNA OXYGEN TAKES PROTON tRNA PEPTIDE BOND BREAKS
H BOND STABILIZES INTERMEDIATE
tRNA OXYGEN TAKES PROTON
tRNA PEPTIDE BOND BREAKS
OXYANION ELECTRONS FORM C O
APPRECIATE !

22. GROWING PEPTIDE HAS BEEN ADDED TO ONE MORE AMINO ACID 21
PEPTIDE BOND FORMS
APPRECIATE !
GROWING PEPTIDE HAS BEEN ADDED TO ONE MORE
AMINO ACID
OR; ONE MORE AMINO ACID HAS BEEN ADDED TO
GROWING PEPTIDE
ADENINE #2451 IS NOW READY TO REPEAT THE PROCESS