Directed Evolution

In this industrial era, where green chemistry is becoming more and more significant, how if we can create enzyme that can catalyse commercially useful reactions. How to do that? Enzymes are made up of proteins, and thus we need to make better proteins than the one which already exists.

How to synthesize better proteins?

Enzymes are made up of proteins which carry out reactions in an organism. We use that enzymes in commercial/industrial processes to get desired outcomes. Thus this biological enzymes are useful in increasing product yield.

So we all are running towards making better enzymes and thus better proteins. We know, proteins are coded out of DNA; so we need to alter some sequence in DNA to code for more efficient  proteins . 

and let me mention this: Playing with DNA is not that easy. If we want to make a change in DNA, there are actually millions of change possible. Thus it is practically impossible to try millions of times and see what results in better enzymes and which doesn’t. Trial and error method is not feasible. In technical terms, we call these changes in DNA, mutations.

So what can we do to make DNA which will code better enzymes. why don’t we use method of evolution which guarantees the better outcome. Its like adopting nature’s method.


First let’s understand in simple terms what is evolution and how does nature do it?

It’s recipe can be summarised in 3 steps.

Introducing Variation , Select the best, proliferate.

Variation:  This means variation in DNA. We know everything that goes on in our body is instructed by DNA – be it the synthesis of Proteins or the colour of our eyes. So whenever a change comes in our DNA , it affects the biology  of our body. 

Selection: actually natural selection. It means that the one who can live better in it’s environment , survives. While the other who are not that compatible, dies. So we are left with only the best species ( and other not so good species extinct)

Proliferate: it means the rapid growth of the species. Thus the organisms are evolved into a good population of best species. And they keep on reproducing. It does not stop here. The selection of the best is always going on In the nature. Thus, evolution is continuous process.

It’s simple and elegant! But the thing is it is so slow. It takes millions of years .

Frances arnold has find out of way to speed up evolution.

Arnold’s Nobel prize winning work.

Here’s the Nobel Prize winning Idea. This method is called directed evolution. Directed evolution starts off with an enzyme that has properties similar to the desired ones. In her earliest work, Arnold (Nobel Prize winner for this discovery) created an enzyme that cleaves peptide bonds in organic solvents. The natural protein only does this in water – in fact, organic solvents change its structure and stop it working.

Arnold then introduced random changes – mutations – into the gene that encodes the peptide-cleaving enzyme. Different versions of the mutated gene were then inserted into bacteria that started churning out many, slightly different enzymes. Arnold then selected the bacteria whose enzymes worked best in organic solvents and subjected them to further rounds of test-tube evolution.

After only three generations, an enzyme was created that worked 256 times better in organic solvents than the original type.

This is success!

This method has helped us make much more efficient enzymes giving boosts in the field of production of bio-fuels, detergents, pharmaceuticals drugs and much more and that too without any harm to nature. Green Chemistry is so important. 

This is just the beginning of era of Directed evolution. tell me in the comment section if you are also excited about this like me.

Stay Curious!


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