Molecular high-speed origami: Researchers elucidate important mechanism of protein folding

May 09, 2014
This image shows a GroEL/ES nano-cage (light blue and white) with encapsulated substrate protein (orange). Credit: Andreas Bracher / Copyright: MPI of Biochemistry

Proteins are the workhorses of the cell and thus responsible for almost all biological functions including metabolism, signal transmission or the determination of the cell's shape. However, before they can fulfill their various tasks, the chain-like molecules must first adopt an intricate three-dimensional conformation. This process is called protein folding and is one of the most important processes in biology. In fact, in the event of improper folding, proteins are often no more able to carry out their duties, or even tend to clump together in aggregates. This in turn can lead to severe diseases like Alzheimer's or Parkinson's. In order to avoid this, specialized proteins, the so-called chaperones, help other proteins to adopt their proper shape.

The bacterial GroEL and GroES serve as an example for this principle: together, they build up a cage-like structure in which they encapsulate new, not yet folded proteins, thereby al-lowing them to fold properly. However, the exact way in which this is accomplished has so far been unclear and is a research topic of the MPIB team led by Manajit Hayer-Hartl and F. Ulrich Hartl, in collaboration with John Engen from Northeastern University in Boston.

Active acceleration of folding

"Our results demonstrate that the chaperones not only prevent clumping, but also dramatically accelerate the folding process", explains Florian Georgescauld, scientist at the MPIB. "Surprisingly, the chaperones achieve this by changing the mechanism of folding: Instead of folding in one large single block, the protein gets its final structure in a series of small, rapid steps – like an elaborate high-speed Origami." The researchers think that splitting up the reaction might render it energetically more favorable, which in turn would lead to increased speed. Hence, the folding process is finished in a few seconds rather than in several minutes.

The study shows for the first time that chaperones can act not only passively, by preventing aggregation, but as an active folding cage that catalyzes the folding process. This results in a high-speed folding mechanism which is of particular biological relevance, so the researchers say, since in this way proteins can be folded faster than they are produced. Thus, a backlog of proteins which are not yet or improperly folded and the disastrous consequences which might go along with this can be avoided. [HS]

Explore further: Chemical chaperones have helped proteins do their jobs for billions of years

More information: F. Georgescauld, K. Popova, A. J. Gupta, A. Bracher, J. R. Engen, M. Hayer-Hartl and F. U. Hartl: GroEL/ES Chaperonin Modulates the Mechanism and Accelerates the Rate of TIM-Barrel Domain Folding. Cell, May 8, 2014. DOI: 10.1016/j.cell.2014.03.038

add to favorites email to friend print save as pdf

Related Stories

New insights to the function of molecular chaperones

Aug 25, 2012

(Phys.org)—Heidelberg molecular biologists have gained new insights into the function of so-called molecular chaperones in protein synthesis. The team headed by Dr. Günter Kramer and Prof. Dr. Bernd Bukau ...

Protein folding becomes cancer treatment target

Dec 03, 2013

(Medical Xpress)—A molecule that helps cancer cells to keep dividing could be a promising target for new treatments, according to research published in the journal Oncogene.

Recommended for you

Molecular gate that could keep cancer cells locked up

2 hours ago

In a study published today in Genes & Development, Dr Christian Speck from the MRC Clinical Sciences Centre's DNA Replication group, in collaboration with Brookhaven National Laboratory (BNL), New York, ...

The 'memory' of starvation is in your genes

5 hours ago

During the winter of 1944, the Nazis blocked food supplies to the western Netherlands, creating a period of widespread famine and devastation. The impact of starvation on expectant mothers produced one of the first known ...

Sugar mimics guide stem cells toward neural fate

Jul 30, 2014

Embryonic stem cells can develop into a multitude of cells types. Researchers would like to understand how to channel that development into the specific types of mature cells that make up the organs and other structures of ...

User comments : 0