Question

Explain how the denaturation-renaturation process occurs aided by chaperoning. You must include at least 2 factors that can denature a protein. Discuss why the shape of a protein is fundamental to its function

Answer 1

1. In Renaturation (Folding) aided by the chaperoning, the chaperonin (barrel-shaped enzymes that helps in the folding of substrates in the course of ATP-driven cycle of encapsulation and release) increases hydration of the water (crucial for the folding of proteins), and also the density of the water which surrounds the denatured (Unfolded) protein to drive correct renaturation (re-folding) .
2. A chaperonin cavity (mainly polar residues on the inner surface of chaperonin) has capacity of accumulation of water near its surface which is useful in catalyzing folding.
3. They bind to partly folded polypeptide chains and aid them for the most favorable folding (energetically) pathway. Hence, Chaperones make the folding process more consistent.

Factors that denatured the Protein:

1. As Urea is chaotrophe, it destabilizes the internal bonds and denatured the protein.
2. The most important factor is Heat, which disrupts H-bonds and also their non-polar hydrophobic interactions.
3. Ultraviolet light effects can also denature the protein which is same like heat.

We know that the three-dimensional shape of a protein is depends on the sequence or long chain of each amino acid that forms a protein, and hence a particular shape of protein molecule determines its function in a cell.

Each amino acid is linked through amide bond, and therefore they are called as Polypeptides.

The non-covalent interactions that are among different parts of the polypeptide chain are responsible for the stable folding structure.

Hence, the shape of protein is fundamental to its function.