9 - Ribosome Flashcards
1
Q
ribsome architechture
A
- largue subunit
- small subunit
- tRNA
- newly synthesized mRNA
2
Q
binding sites in the ribosome
A
- A site
- P site
- E site
3
Q
polypeptide synthesis in binding sites
A
- amino acid in tRNA (in A site) will act as the Nu- and attack the ester linkage which will connect the polypeptide to the P-site
- when a stop codon is encountered, the ester is hydrolyzed to give the C terminus (carbonyl)
4
Q
ribozyme
A
the ribosome is a ribozyme as it is a RNA synthesizing catalyst
5
Q
elongation factor (EF)
A
forms a complex with tRNA and will dissociate (along with the hydrolysis of GTP) once it is delivered to the proper A site
6
Q
sarcin-ricin loop (SRL)
A
- close to where GTP is hydrolyzed
7
Q
ricin
A
- enzyme comes from castor bean
- 1 molecule will kill the entire cell3
- 2 subunits that will dissociate from each other once it enters the cell
- the catalytic part is an enzyme that will hydrolyzes adenine base in the SRL
- hydrolyzing adenine prevents EF binding as it will not recognize
- protein synthesis will terminate
- will continue to hydrolyze and terminate protein synthesis until cell is dead
8
Q
release factor
A
- reads stop codons and will bind to A site
- similar structure as tRNA
9
Q
protein folding
A
full protein cannot fully fold until the whole chain has exited the tunnel
10
Q
erythromycin A
A
- targets exit tunnel
- blocks protein from exiting the tunnel
- protein synthesis will terminate
11
Q
exit tunnel
A
- polypeptide chains exit the tunnel to form proteins and can be targeted specifically
- diversity in different tunnels because of mutations
