I was asked a question as to what is so special with Taq Polymerase that makes it quite stable at high temperatures though its functioning is the same as other DNA polymerases like that of mesophiles.

I just think it's the adaptation of that particular bacteria in that high-temperature environment. But I want to know if there is any strong reason for this stability.


Well, the evolutionary reason is the one you mentioned: the thermostability of Taq allowed its bacterium to colonize high-temperature environments. That, however, does not say anything about the molecular reasons for this difference.

I found this very good answer on Quora. The end of the post has several references for its claims.

Long story short, the stability of a proteins folded state depends on the difference of free energy $\Delta G$ between the folded and unfolded states. However, $\Delta G = \Delta H - T \Delta S$, which means the difference in free energy can either come from a bigger difference in enthalpy (for example, salt bridges, hydrogen bonds, hydrophobic interactions and such in the folded state) or a smaller difference in entropy (for example, a low number of "not-rigid" amino acids like glycin , or a high release of water from folding).

While enthalpy is often the reason for stability of folding, it seems like for Taq polymerase the difference actually lies in an unusually small difference in entropy between the two states.

Edit: here is one of the best references of the post. Open the link above to find more. https://www.ncbi.nlm.nih.gov/pubmed/24174290

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    $\begingroup$ Can you please cite an original source i.e. a research article/review? $\endgroup$ – WYSIWYG Oct 22 '19 at 8:01
  • $\begingroup$ @WYSIWYG As I said, the end of the post I linked had all the references. Anyway, here you go: ncbi.nlm.nih.gov/pubmed/24174290 $\endgroup$ – allepasse Oct 22 '19 at 8:34
  • $\begingroup$ Please edit your answer to include this reference information — comments are intended for suggestions and discussions intended to improve answers (or questions) and should not be used to post material that belongs in the answer itself. You also might want to consult the help pages for additional advice on How to Answer effectively on this site. Thanks! 😊 $\endgroup$ – tyersome Oct 23 '19 at 17:56

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