tRNA Flashcards
Revision
tRNA
Adapter RNA/ transfer RNA
Role?
- Translation
- Primer during Reverse Transcription of Retrovirus
Size
75 - 95 ntds.
Mostly 76 ntds
Present in
- Cytosol
- Semi-autonomous Organelle
First Sequenced
Yeast tRNA^ala
2D / Secondary structure
clover leaf like
Well defined stems and loops
Acceptor arm
- 7 BP
- 4 unpaired ntds.
(includes CCA in all tRNA)
Anticodon Arm
- 5-6 BP
- Loop having Anticodons
TΨC
- Ψ is Pseudouridylation
- 5 BP
- contains modified Bases- Pseudouridine
D-arm
- 3-4 BP
- D is Dihydrouridine
- Contains modified Bases- Dihydrouridine
Variable Loop
- 4-5 ntds. actually
- 10-24 max
Modified bases are mainly present in_____
Loop
Due to modification, they won’t be able to base pairing within?
within tRNA
Shape of Tertiary Structure?
L-shape
1st extended helix
Acceptor arm + TΨC
2nd extended helix
Anticodon loop + D-arm
_____ bond formed b/w bases
Hydrogen
Unusual Bases in _____?
Primary structure
Examples of Unusual Bases?
- Pseudouridine
- Dihydrouridine
- Hypoxanthine/Inosine
- Thymine
- Methyl Guanine
Unusual bases (conc. in the loop) disrupt the ____
Formation of Hydrogen bond
Potential recognition sites for various proteins are present in
in the region of Conc. Unusual bases
Modified bases are essential for tRNA.
true or False?
False
Cells lacking these unusual bases show___
reduced rates of growth
These unusual bases lead to___
Improved tRNA Function
