Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Birth Of An Enzyme

25.03.2008
Scientists succeed in designing artificial enzymes that also undergo 'evolution in a test tube'

A team of scientists from the University of Washington, Seattle, and the Weizmann Institute of Science, Israel, has succeeded in creating a new type of enzyme for a reaction for which no naturally occurring enzyme has evolved, by using a combination of novel computational methodologies and molecular in vitro evolution. This achievement opens the door to the development of a variety of potential applications in medicine and industry.

Mankind triumphed in a recent 'competition' against nature when scientists succeeded in creating a new type of enzyme for a reaction for which no naturally occurring enzyme has evolved. This achievement opens the door to the development of a variety of potential applications in medicine and industry.

Enzymes are, without a doubt, a valuable model for understanding the intricate works of nature. These molecular machines - which without them, life would not exist - are responsible for initiating chemical reactions within the body. Millions of years of natural selection have fine-tuned the activity of such enzymes, allowing chemical reactions to take place millions of times faster. In order to create artificial enzymes, a comprehensive understanding of the structure of natural enzymes, their mode of action, as well as advanced protein engineering techniques is needed. A team of scientists from the University of Washington, Seattle, and the Weizmann Institute of Science, Israel, made a crucial breakthrough toward this endeavor. Their findings have recently been published in the scientific journal Nature.

Enzymes are biological catalysts that are made from a string of amino acids, which fold into specific three-dimensional protein structures. The scientists' aim was to create an enzyme for a specific chemical reaction whereby a proton (a positively charged hydrogen atom) is removed from carbon - a highly demanding reaction and rate-determining step in numerous processes for which no enzymes currently exist, but which would be beneficial in helping to speed up the reaction. During the first heat of the 'competition,' the research team designed the 'heart' of the enzymatic machine - the active site - where the chemical reactions take place.

The second heat of the competition was to design the backbone of the enzyme, i.e., to determine the sequence of the 200 amino acids that make up the structure of the protein. This was no easy feat seeing as there is an infinite number of ways to arrange 20 different types of amino acids into strings of 200. But in practice, only a limited number of possibilities are available as the sequence of amino acids determines the structure of the enzyme, which in turn, determines its specific activity. Prof. David Baker of the University of Washington, Seattle, used novel computational methodologies to scan tens of thousands of sequence possibilities, identifying about 60 computationally designed enzymes that had the potential to carry out the intended activity. Of these 60 sequences tested, eight advanced to the next 'round' having showed biological activity. Of these remaining eight, three sequences got through to the 'final stage,' which proved to be the most active. Drs. Orly Dym and Shira Albeck of the Weizmann Institute's Structural Biology Department solved the structure of one of the final contestants, and confirmed that the enzymes created were almost identical to the predicted computational design.

But the efficiency of the new enzymes could not compare to that of naturally-occurring enzymes that have evolved over millions of years. This is where 'mankind' was on the verge of losing the competition to nature, until Prof. Dan Tawfik and research student Olga Khersonsky of the Weizmann Institute's Biological Chemistry Department stepped in, whereby they developed a method allowing the synthetic enzymes to undergo 'evolution in a test tube' that mimics natural evolution. Their method is based on repeated rounds of random mutations followed by scanning the mutant enzymes to find the ones who showed the most improvement in efficiency. These enzymes then underwent further rounds of mutation and screening. Results show that it takes only seven rounds of evolution in a test tube to improve the enzymes' efficiency 200-fold compared with the efficiency of the computer-designed template, resulting in a million-fold increase in reaction rates compared with those that take place in the absence of an enzyme.

The scientists found that the mutations occurring in the area surrounding the enzyme's active site caused minor structural changes, which in turn, resulted in an increased chemical reaction rate. These mutations therefore seem to correct shortcomings in the computational design, by shedding light on what might be lacking in the original designs. Other mutations increased the flexibility of the enzymes, which helped to increase the speed of substrate release from the active site.

'Reproducing the breathtaking performances of natural enzymes is a daunting task, but the combination of computational design and molecular in vitro evolution opens up new horizons in the creation of synthetic enzymes,' says Tawfik. 'Thanks to this research, we have gained a better understanding of the structure of enzymes as well as their mode of action. This, in turn, will allow us to design and create enzymes that nature itself had not 'thought' of, which could be used in various processes, such as neutralizing poisons, developing medicines, as well as for many further potential applications.'

Prof. Dan Tawfik's research is supported by the J & R Center for Scientific Research; the Jack Wolgin Prize for Scientific Excellence; Mr. and Mrs. Yossie Hollander, Israel; Mr. Rowland Schaefer, New York, NY; and the estate of Fannie Sherr, New York, NY. Prof. Tawfik is the incumbent of the Elaine Blond Career Development Chair.

The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,600 scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.

Weizmann Institute news releases are posted on the World Wide Web at
http://wis-wander.weizmann.ac.il, and are also available at http://www.eurekalert.org.

Yivsam Azgad | idw
Further information:
http://wis-wander.weizmann.ac.il

Further reports about: Active Computational Efficiency Mutation acids activity amino amino acids determine enzyme reaction

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>