why dna denaturization reversible but not protein denaturization?

Question

why dna denaturization reversible but not protein denaturization?

Answer 1

DNA has a very regular three dimentional structure. All DNA in water regardless of how big and what sequence it is, forms a left hand double helix (known as the B-form). That form is determind by the DNA backbone which is the same for all DNA.

On the other hand protein's 3-D sturcture is determind by the side chains of the amino acid and the sequence those amino acids are in. And since every amino acid has a different side chain, and there are 20 different amino acids, the possible combination of interactions are huge. And thus, if you denature it the likilyhood of the protein refolding back to the orginal shape is very small. But it can be done in some cases, there is a few proteins that will fold back after denaturization if the conditions are exactally right.

Answer 2

Just a guess, but protein denaturalization is scrambling the entire protein molecule, that is, the slightest difference in shape will change the tertiary and quaternary structure (and if you denaturalize further the primary and seconddary) structures of the protein. However for dna denaturalization included may kep strands intact, breaking only the bonds between the bases or that it only invvolves methylization of certain parts ( which obviously is reversibl... well not obviously).... sorry if this is not what you mean or there is a wrong term.

Answer 3

DNA self-associates in a relatively simple way and therefore can renature quite easily.

Most proteins have highly complex tertiary and quaternary structures and often fold with the assistance of so-called chaperone proteins that help them attain their final tertiary structure. After denaturation they are not able to self-assemble spontaneously because of this.