Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Rehydrate -- your RNA needs it

Water, that molecule-of-all-trades, is famous for its roles in shaping the Earth, sustaining living creatures and serving as a universal solvent.

Now, researchers at the University of Michigan and the Academy of Sciences of the Czech Republic have uncovered two previously unknown roles for water in RNA enzymes, molecules which themselves play critical roles in living cells and show promising medical applications.

The researchers' findings will be published online in the Proceedings of the National Academy of Sciences (PNAS) this week.

RNA enzymes, also known as ribozymes, accelerate chemical reactions inside cells, just as their better-known protein counterparts do. And just as a protein enzyme is not a static structure, a ribozyme also changes shape, cycling back and forth between active and inactive forms (called conformations).

In earlier work, a team led by U-M's Nils Walter, associate professor of chemistry, found that modifications made anywhere on the ribozyme molecule---even far from the site where the chemical reaction occurs---affect the rates at which the enzyme changes conformation and catalyzes the reaction. Something similar had been seen in protein enzymes, but never before in RNA enzymes.

The earlier finding, published in PNAS two years ago, suggested that information about changes in distant parts of the ribozyme travels through some sort of network to the core of the molecule, where chemical reactions take place. The latest work shows that water molecules trapped inside the ribozyme's core are essential components of that network.

The network acts like a jostling crowd at a cocktail party, where hydrogen bonds---weak, electrostatic attractions between molecules or parts of molecules---take the place of handshakes. Water molecules trapped in ribozymes can form hydrogen bonds with other water molecules or with parts of the ribozyme molecule.

"The way we interpret the data is that in ribozymes, a chemical modification introduced at one place changes the local structure slightly," Walter said. The building blocks making up the ribozyme wiggle into different positions and in the process must let go of some hydrogen bonds and form others, just as partygoers shift position and engage with other guests.

"As a consequence, their hydrogen bonding partners---some of which are water molecules---also rearrange. Then their hydrogen bonding partners also rearrange, creating a domino effect, where a local modification spreads throughout the molecule and modifies the structure elsewhere, even at quite a distance," Walter said. Water facilitates the process by increasing the number of hydrogen bonds and making the ribozyme behave as an interconnected whole.

Walter and coworkers also found evidence that water is directly involved in catalyzing reactions in the ribozyme's core, another previously unknown role. The research team explored the new roles of water molecules using a combination of computational simulations and a technique called single-molecule fluorescence resonance energy transfer (FRET), which allowed the researchers to directly observe and measure how quickly the ribozyme switched forms and how the rates changed when various parts of the molecule were altered.

The situation in ribozymes contrasts with what happens in protein enzymes, which repel water from their cores and rely on direct contact, rather than a network of hydrogen bonds, to communicate structural changes from one part of the molecule to another.

So far, the researchers have focused on one particular ribozyme, but Walter predicts the findings will apply to other RNAs. If so, those findings should be of great interest to scientists who are learning more all the time about the diverse roles of RNA. Once thought to be only a passive carrier of encoded genetic information, RNA is now known to regulate gene expression and other important cellular processes and to act as a sort of sensor---detecting cellular signals and carrying out appropriate reactions in response. In fact, there are many more so-called non-protein coding RNAs in the cell (around 100,000 in humans), which are not translated into protein, than there are protein coding messenger RNAs (about 25,000), making these vast numbers of RNA molecules central players in our bodies.

Work is also underway in academic and industrial labs around the world to engineer RNA for medical purposes. The engineered molecules, called RNA aptamers, are selected for their ability to bind to particular proteins involved in certain diseases, blocking key steps in the disease process.

"It's likely that water helps mediate the binding between these aptamers and their disease-causing protein targets, ultimately keeping the protein away from where it can wreak havoc," Walter said. "So the fundamental understanding we are gaining of the role of water in RNA almost certainly will have relevance in the treatment or prevention of disease."

Nancy Ross-Flanigan | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

Advanced analysis of brain structure shape may track progression to Alzheimer's disease

26.10.2016 | Health and Medicine

More VideoLinks >>>