What makes enzymes such effective "molecular workers".
By Marit Selvin
Dr. Dan Tofik from the Department of Biological Chemistry at the Weizmann Institute deals with one
Life's Most Basic Questions: How Enzymes Were Created. this question
Touches the essence of life, since enzymes are proteins that serve as catalysts of
All life processes in the cell, starting with the breakdown of food and ending with building proteins
and new cells. Evolution has given enzymes tremendous abilities, above
And beyond any man-made chemical catalyst. Chemical reactions that continue
Hundreds of millions of years end in a thousandth of a second with the participation of enzymes.
This, for example, happens in the process of creating the genetic material, DNA, from the starting materials
his, or in the processing of the DNA during its replication - two reactions that fill
A key role in the life process. Another example: the biochemical process responsible
On the transmission of the nerve message from the brain to the organs of movement. the living creatures
We owe their ability to move to the enzyme that brings this process to an end
in the millionth of a second; Without it it would have lasted many months.
The involvement of enzymes in life processes, starting with the creation of single cells
The most primitive, including complex human beings, raises the question
How did the enzymes develop and thereby enable living things to cope with the process
Evolution with changing environmental conditions. The evolution of species, according to
Darwin and the theories that followed him, driven by natural selection
and is based on the fact that individuals of the same species are different from each other. When
Changes occur in environmental conditions, those individuals whose DNA has passed
Mutations that allow them to cope with environmental changes, survive.
Until recent times, the study of evolution was limited to organisms, ie
For systems containing at least one complete cell, bacteria for example. Today is surfing
The study of evolution at the molecular level. Scientists believe that the enzymes too
have evolved, according to the same principles. In response to environmental stress were created
Enzymes that were able to participate in the new chemical processes that were required
in order to cope with the new environmental conditions. But it turns out not all
The new enzymes developed alongside the evolution of living things. "During
For years, scientists said: why is it that enzymes are so effective? After all, they had
Billions of years to evolve," says Dr. Toufik. "Today suddenly
Discover new enzymes that have developed in a very short time. For example, in bacteria
An enzyme was found in the soil that knows how to break down a pesticide that appeared on the surface of a ball
The country 60-50 years ago in total. The bacteria 'learned' to break down the new material
Because it was the only source of organic phosphorus in the soil. The question is how
A new enzyme is created with such great speed, in a flash of the second in terms
evolutionary".
The answer to this is the basis of Toufik's research in the field of evolution
the enzymes. Tofik believes that every protein in the living world has a primary activity
And side activities that he calls "Khaltura activities". everytime
that there is no need for the side activity, it is not manifested, but as soon as it is created
Environmental stress that threatens the life of the organism, the activity joins
Haltorist and helps him survive. "Suppose, for example, that apart from my work as a researcher,
I also do plumbing work in my free time," explains Toufik. "all
As long as the conditions in the laboratory are reasonable, this feature is not manifested. but
If suddenly a pipe bursts in the laboratory, or then I save the situation. the idea
This explains how enzymes can develop as a result of environmental stress
In such a quick process - they simply went through 'professional retraining' from a profession to a profession
main".
Tofik is trying to prove his idea by creating new enzymes
in the laboratory under conditions that simulate evolution. To this end, he sought to develop a system that is possible
Put many genes into it, apply environmental pressure on them and check if
As a result, they produce new enzymes that know how to deal with
The changing environment. "I was looking for a system where we could test such possibilities
A lot, so that the likelihood that a new enzyme will grow from it will increase", says Toufik.
In collaboration with Dr. Andrew Griffith from the University of Cambridge
In the UK, a producer has created a system consisting of tens of billions of drops
Tiny artificials whose interior is made of water and whose shell is
Fat. "It is an emulsion of oil and water just like a vinaigrette or cream sauce
face, and some call it 'evolution in vinaigrette,'" says Tofik.
Inside each such drop, one gene is inserted, and together with it, the drop is equipped
in the substances that participate in turning the gene into a protein. In the end Christians in all
Drop many copies of the protein that the gene encodes, and that's how I have a product
Tens of billions of different proteins.
In the next step, an environmental stress product is created on the genes in the droplets. for example:
A poison molecule is attached to each drop. If in certain drops are found
Proteins (enzymes) that know how to break down the poison, an attachment is formed between
The gene in the drop and the breakdown product of the poison. Based on this engagement
An isolate will produce the gene encoding the enzyme that breaks down the poison from the other genes
in drops "This system makes it possible to fish genes that already exist and transfer them
them with the help of gradual changes from minor to main profession", he says
Toufik, "and also to get out of completely accidental pieces of DNA and find from them
New enzymes. This is how we mimic the way enzymes are formed
in nature".
The process of evolution that you will imitate in the laboratory opens up many possibilities. "It is possible
Basically take the entire human genome, make many changes (mutations)
in genes and look for a new enzyme based on a pre-tailored activity", he says
will produce Thus, for example, Mikva Tuofik hopes that it will be possible to create enzymes that will help
effectively kill cancer cells, or an enzyme that will help protect against gases
nerves.
Other application possibilities are in the field of chemistry. in the processes of chemical catalysis
which is used for many industrial needs, from nylon production to pharmaceuticals,
Chemical catalysts are used that act like enzymes, but
slowly Most chemical catalysts are toxic metals that work
at very high temperatures and pressure. The enzymes are natural substances
Environmentally friendly, operating at low temperatures - very effective
More. Tofik believes that using the method he developed, enzymes will be found that will be more efficient
Chemical processes without causing damage to the environment.
Dr. Toufik. Chemical reactions that last hundreds of millions of years are completed with the help of enzymes in a millisecond
