Question

The observation that proteins often renature into their original conformations after they have been unfolded by denaturing solvents implies that ...

A. the information needed to specify the three-dimensional shape of a protein is encoded in its amino acid sequence.
B. the cell does not need molecular chaperones for survival.
C. the final folded structure of a protein is usually NOT the one with the lowest free energy.
D. each protein folds into several different conformations inside the cell.
E. All of the above.

Answer 1

The ability of proteins to renature indicates that their three-dimensional shapes are determined by their amino acid sequences. Protein chaperones may assist in the folding process, but the primary sequence is key to the protein's structure.

Step-by-step explanation:

The observation that proteins often renature into their original conformations after they have been unfolded by denaturing solvents implies that the information needed to specify the three-dimensional shape of a protein is encoded in its amino acid sequence. This means that the sequence of amino acids, as dictated by the mRNA, is fundamental in determining the protein's native structure. Proteins may undergo denaturation due to changes in their environment, such as variations in temperature or pH, but this process usually does not affect their primary structure consisting of the amino acid sequence.

It is recognized that many proteins fold spontaneously, but to avoid incorrect folding or aggregation, protein chaperones may be required to assist in the folding process. Therefore, while the intrinsic sequence of a protein dictates its potential to fold into the correct shape, cellular mechanisms such as chaperones play a crucial role in ensuring that the folding pathway results in a functional protein.