translation Flashcards
what sequence is used to initiate translation
the shine-Dalgarno sequence
what binds to the shine-Dalgarno seq?
the 16SrRna
what tNRA binds to the start codon
fMet-tRNA. this tRNA holds a special met AA that has a modified side chain with a carbonyl group attached to the NH group.
once translation beings, this AA will fall off
translation initiaion
initiation factors 1 and 3 and 30s ribosome unit assemble around the start codon. IF 2(with GTP follow )and attach fMET.
once fMET is a match, the IF 1 and 3 disassociate and GTP is hydrolyzed to attach the incoming 50s sub unit
translation elongation
promoted by EF-Tu-GTP. this protein guides the tRNA moles to the A site. when the tRNA matches the condo, the GTP is hydrolysed to power the ester linkage and transfer of the growing peptide to the A site.
what kind of catalysis is used during elongation?
catalysis by orientation and approximation
how are peptide bonds formed?
the NH2 group of the AA in the A site nuc attacks the carbonyl of the bottom AA on the peptide chain. the peptide bond is formed and the peptide is related from the tRNA in the p site and is transferred to the tRNA in the A site this transfer is cata by the hydrolysis of GTP by EF-Tu which also moves the ribosome over. the A enters the P site
translation termination
RF 1 or 2 prot recognizes a conserved sequence. these proteins do not have any AA attached to them, to the peptide is cleaved and released. once released, RF 3 will hydrolyze GTP to release the RF and disassemble the ribosome
which proteins are commonly modified
those that contian hydroxyl, thiol or amino func groups. this is because they. are creative due to their polariy and are able to interact with other residues of other proteins
what are restriction enzymes and how are they used
bacterial enzymes with endo nuc actively, able to cleave specific sequences found on both DNA strands.
they are used to insert desired protein-coding sequences. commonly used to derive desired products through gene expression.
