Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research at UNC shows ribosomes do not function as conventional enzymes

11.05.2004


Contrary to what some scientists have suggested, key intracellular particles known as ribosomes serve as mechanical matchmakers or readout devices rather than acting chemically to speed up reactions in the body the way enzymes do, University of North Carolina at Chapel Hill researchers and colleagues have discovered.



A report on the findings by Drs. Annette Sievers and Richard Wolfenden of the UNC School of Medicine appears in the new issue of the Proceedings of the National Academy of Sciences.

Besides Sievers and Wolfenden, report authors are doctoral student Malte Beringer and Dr. Marina V. Rodnina of the University of Witten/Herdecke in Witten, Germany.


"Enzymes, of which we have hundreds, participate chemically in the transformation of biological molecules by making and breaking bonds," said Wolfenden, Alumni Distinguished professor of biochemistry and biophysics. "A hallmark of that direct chemical involvement is that their catalytic effects are extremely temperature dependent. The question was whether the ribosome acts as an enzyme since there has been considerable interest in whether this particle does that."

Ribosomes are critical sites of protein synthesis, he said. Inside those particles, amino acids are laid down in proteins in the order specified by the genetic code.

In general, enzymes, which are biological catalysts, facilitate a chemical transformation by lowering the energy barrier, Sievers said.

"One can imagine this as two paths over a mountain," she said. "The path without the enzyme is much higher, and so it takes more energy to cross the mountain. The path on the enzyme is lower, and so it is easier to follow it."

Energy has two components, Sievers said. One is heat (enthalpy), the other one refers to the order of a system (entropy). It’s possible for an enzyme to lower either of those energy components. Direct chemical involvement of an enzyme is characterized by lowering the enthalpy of the activation barrier and has often been observed.

"In our present work we tested the contribution of enthalpy and entropy to lowering the activation energy barrier," she said. "Malte did this by comparing the energy barrier of the reaction when the ribosome was present, and I did it when the ribosome was not present."

The reactions both with the ribosome present and without the ribosome have the same enthalpic activation barrier, the researchers found.

"The means by which the ribosome speeds up the chemical transformation is purely entropic in origin -- the ribosome acts as a mechanical readout device, rather than speeding up the reaction in the way that conventional enzymes do," Sievers said.

The experiments will help scientists narrow their view of how ribsomes function and understand them better, Wolfenden said.

"Annette and Malte’s discovery has important implications for the design of inhibitors of protein synthesis and might ultimately furnish a new basis for drug design," he said. "Their work shows that the ribosome’s effect is to introduce order into chaos."

David Williamson | EurekAlert!
Further information:
http://www.unc.edu/

More articles from Life Sciences:

nachricht Cell Division at High Speed
19.06.2019 | Julius-Maximilians-Universität Würzburg

nachricht Monitoring biodiversity with sound: how machines can enrich our knowledge
18.06.2019 | Georg-August-Universität Göttingen

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Successfully Tested in Praxis: Bidirectional Sensor Technology Optimizes Laser Material Deposition

The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.

Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

A new manufacturing process for aluminum alloys

19.06.2019 | Materials Sciences

Inhaling air pollution-like irritant alters defensive heart-lung reflex for hypertension

19.06.2019 | Health and Medicine

Innovative powder revolutionises 3D metal printing

19.06.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>