Which of the following best lists the correct order of the steps taken to produce human insulin in
E.coli in the 1970s?
I. | Each insulin chain was cloned into an expression vector as a continuation of the lacZ reading |
frame, resulting in a fusion protein for each chain.
II. | Disulfide bonds were induced to form between the cysteine residues of the purified insulin A |
and B chains.
III. | Both human insulin genes were reverse translated to create synthetic genes. |
IV. | EcoRI and BamHI restriction sites were added to the ends of the DNA to facilitate directional |
cloning of each into a separate plasmid vector.
◦ I, II, III, IV
◦ III, IV, I, II
◦ IV, III, I, II
◦ III, I, II, IV
◦ I, III, IV, II