Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > UCLA physicists control chemical reactions mechanically

Giovanni Zocchi
Giovanni Zocchi

Abstract:
UCLA physicists have taken a significant step in controlling chemical reactions mechanically, an important advance in nanotechnology, UCLA physics professor Giovanni Zocchi and colleagues report.

UCLA physicists control chemical reactions mechanically

Los Angeles, CA | Posted on September 17th, 2010

Chemical reactions in the cell are catalyzed by enzymes, which are protein molecules that speed up reactions. Each protein catalyzes a specific reaction. In a chemical reaction, two molecules collide and exchange atoms; the enzyme is the third party, the "midwife to the reaction."

But the molecules have to collide in a certain way for the reaction to occur. The enzyme binds to the molecules and lines them up, forcing them to collide in the "right" way, so the probability that the molecules will exchange atoms is much higher.

"Instead of just watching what the molecules do, we can mechanically prod them," said Zocchi, the senior author of the research.

To do that, Zocchi and his graduate students, Chiao-Yu Tseng and Andrew Wang, attached a controllable molecular spring made of DNA to the enzyme. The spring is about 10,000 times smaller than the diameter of a human hair. They can mechanically turn the enzyme on and off and control how fast the chemical reaction occurs. In their newest research, they attached the molecular spring at three different locations on the enzyme and were able to mechanically influence different specific steps of the reaction.

They published their research in the journal Europhysics Letters, a publication of the European Physical Society, in July.

"We have stressed the enzyme in different ways," Zocchi said. "We can measure the effect on the chemical reaction of stressing the molecule this way or that way. Stressing the molecule in different locations produces different responses. If you attach the molecular spring in one place, nothing much happens to the chemical reaction, but you attach it to a different place and you affect one step in the chemical reaction. Then you attach it to a third place and affect another step in this chemical reaction."

Zocchi, Tseng and Wang studied the rate of the chemical reactions and reported in detail what happened to the steps of the reactions as they applied mechanical stress to the enzyme at different places.

"Standing on the shoulders of 50 years of structural studies of proteins, we looked beyond the structural description at the dynamics, specifically the question of what forces — and applied where — have what effect on the reaction rates," Zocchi said.

In a related second paper, Zocchi and his colleagues reached a surprising conclusion in solving a longstanding physics puzzle.

When one bends a straight tree branch or a straight rod by compressing it longitudinally, the branch or rod at first remains straight and does not bend until a certain critical force is exceeded. At the critical force, it does not bend a little — it suddenly buckles and bends a lot.

"This phenomenon is well known to any child who has made bows from hazelnut bush branches, for example, which are typically quite straight. To string the bow, you have to press down on it hard to buckle it, but once it is bent, you need only a smaller force to keep it so," Zocchi said.

The UCLA physicists studied the elastic energy of their DNA molecular spring when it is sharply bent.

"Such a short double-stranded DNA molecule is somewhat similar to a rod, but the elasticity of DNA at this scale was not known," Zocchi said. "What is the force the DNA molecular spring is exerting on the enzyme? We have answered this question.

"We find there is a similar bifurcation with this DNA molecule. It goes from being bent smoothly to having a kink. When we bend this molecule, there is a critical force where there is a qualitative difference. The molecule is like the tree branch and the rod in this respect. If you're just a little below the threshold, the system has one kind of behavior; if you're just a little above the threshold force, the behavior is totally different. The achievement was to measure directly the elastic energy of this stressed molecule, and from the elastic energy characterize the kink."

Co-authors on this research are UCLA physics graduate students Hao Qu, Chiao-Yu Tseng and Yong Wang and UCLA associate professor of chemistry and biochemistry Alexander Levine, who is a member of the California NanoSystems Institute at UCLA. The research was published in April, also in the journal Europhysics Letters.

"We can now measure for any specific DNA molecule what the elastic energy threshold for the instability is," Zocchi said. "I see beauty in this important phenomenon. How is it possible that the same principle applies to a tree branch and to a molecule? Yet it does. The essence of physics is finding common behavior in systems that seem very different."

While Zocchi's research may have applications for medicine and other fields, he emphasizes the advance in knowledge itself.

"There is value in science that adds to our knowledge and helps us understand our world, apart from the value of future applications," he said. "I study problems that I find interesting, where I think I can make a contribution. Why study a particular problem rather than another? Perhaps for the same reason a painter chooses a particular landscape. Perhaps we see beauty there."

####

About UCLA
UCLA is California's largest university, with an enrollment of nearly 38,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 323 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Five alumni and five faculty have been awarded the Nobel Prize.

For more information, please click here

Contacts:
Media Contacts
Stuart Wolpert,
310-206-0511

Copyright © UCLA

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

The Hiden EQP Plasma Diagnostic with on-board MCA July 22nd, 2014

Bruker Awarded Fourth PeakForce Tapping Patent: AFM Mode Uniquely Combines Highest Resolution Imaging and Material Property Mapping July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Penn Study: Understanding Graphene’s Electrical Properties on an Atomic Level July 22nd, 2014

Chemistry

Oregon chemists eye improved thin films with metal substitution: Solution-based inorganic process could drive more efficient electronics and solar devices July 21st, 2014

Fundamental Chemistry Findings Could Help Extend Moore’s Law: A Berkeley Lab-Intel collaboration outlines the chemistry of photoresist, enabling smaller features for future generations of microprocessors July 15th, 2014

Researchers discover boron 'buckyball' July 14th, 2014

Physics

Physicists Use Computer Models to Reveal Quantum Effects in Biological Oxygen Transport: The team solved a long-standing question by explaining why oxygen – and not deadly carbon monoxide – preferably binds to the proteins that transport it around the body. July 17th, 2014

Flashes of light on the superconductor: Using light to modulate the properties of a copper-based superconductor July 15th, 2014

Academic/Education

Haydale Announces Collaboration Agreement with Swansea University’s Welsh Centre for Printing and Coatings (WCPC) July 12th, 2014

STFC takes delivery of the 100th Hitachi Tabletop SEM in the UK July 3rd, 2014

Innovation Management and the Emergence of the Nanobiotechnology Industry July 1st, 2014

Albany NanoCollege Faculty Member Selected as Editor-in-Chief of the Prestigious Journal of Electronic Materials July 1st, 2014

Announcements

Nanometrics Announces Upcoming Investor Events July 22nd, 2014

Bruker Awarded Fourth PeakForce Tapping Patent: AFM Mode Uniquely Combines Highest Resolution Imaging and Material Property Mapping July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Penn Study: Understanding Graphene’s Electrical Properties on an Atomic Level July 22nd, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE