Question

imagine an experiment is done to replace all of the cysteines in chain a with glycines. the structure of glycine is also shown below. how would the changes in experiment most likely impact the structure of the proinsulin protein? select all that apply. the tertiary structure of the protein would likely be altered. this change would not likely impact any levels of the proteins structure. the quaternary structure in the protein would likely be altered. the primary structure of the protein would be altered.

Explanation:

Cysteine has a sulfhydryl group (-SH) which can form disulfide bonds crucial for tertiary and sometimes quaternary structure. Glycine has a simple -H side - chain. Replacing cysteines with glycines will change the primary structure (amino - acid sequence). It will also likely disrupt disulfide - bond formation, altering the tertiary structure. Since this is a single - chain proinsulin (no quaternary structure in this context as quaternary structure involves multiple polypeptide chains), the quaternary structure won't be affected.

Answer:

The tertiary structure of the protein would likely be altered.
The primary structure of the protein would be altered.