Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Opening the cavity floodgates

23.01.2018

Freiburg biochemists investigate the transport of large proteins through bacterial cell membranes

Every cell is surrounded by a membrane, which ensures the internal biochemical milieu and regulates the exchange of substances with its surroundings. In every cell membrane, there are a large number of transporters that allow only one sort of molecule to pass through.


Four TatC molecules (blue) create a circle around four TatB molecules (green) to form a cavity in the center in which the protein to be transported can insert from below. Source: Journal of Biological Chemistry

In the case of very small molecules, such as water, the responsible transporters form tiny pores in the membrane, which disappear immediately after the process. But how are proteins that are thousands of times larger transported through membranes without creating a large leak?

In a recent study, a team led by Prof. Dr. Matthias Müller at the Institute for Biochemistry and Molecular Biology and the special research area 746 along with Prof. Dr. Bettina Warscheid at the Institute of Biology II and the Cluster of Excellence BIOSS Centre for Biological Signalling Studies at the University of Freiburg discovered details about the structure of such a transporter for protein molecules. Their findings have been published in Journal of Biological Chemistry.

The researchers studied the so-called Tat transporter that exists in the cell membrane of bacteria and exports certain proteins, the Tat substrates, out of them. The transporter consists of three components called TatA, TatB and TatC. They are distributed throughout the membrane in a resting state and only assemble into an active transporter when a Tat substrate binds to TatC. So far little is known about how the three components merge.

In a previous study, the researchers had found that the chemical dicyclohexylcarbodiimide (DCCD) blocked the Tat transport. The scientists have now identified a specific position on TatC that can be chemically altered by DCCD, which in turn inhibits contact with the Tat substrate. The position is not located on the TatC surface, but rather in a part hidden deep within the membrane.

Thus, DCCD does not inhibit the primary docking of the Tat substrate, but rather its deep penetration into the membrane along the TatC molecule. Thus, the teams were able to demonstrate that the assembly of several TatC and TatB components creates a cavity in which the Tat substrate inserts from one side of the membrane. It is only in the next step, which must still be explained, that this cavity opens to the outside for which TatA is then necessary.

The Tat transporter could serve to develop new types of antibiotics in the future: Some bacteria that are harmful to human beings use the Tat transport to export protein molecules with whose help they establish contact with human host cells. Ideally, an antibiotic should only inhibit the metabolism of bacteria and not that of patients. Since the Tat transporter does not occur in human cells, it would thus be a suitable antibiotic target.

Original publication:
A. S. Blümmel. F. Drepper, B. Knapp, E. Eimer, B. Warscheid, M. Müller, J. Fröbel. Structural features of the TatC membrane protein that determine docking and insertion of a twin-arginine signal peptide. J. Biol. Chem. 292, 21320 (2017). DOI: 10.1074/jbc.M117.812560

Image caption:
Four TatC molecules (blue) create a circle around four TatB molecules (green) to form a cavity in the center in which the protein to be transported can insert from below. Source: Journal of Biological Chemistry

Contact:
Prof. Dr. Matthias Müller
Institute for Biochemistry and Molecular Biology
University of Freiburg
Tel.: 0761/203-5265
E-Mail: matthias.mueller@biochemie.uni-freiburg.de

Weitere Informationen:

https://www.pr.uni-freiburg.de/pm-en/press-releases-2018/opening-the-cavity-floo...

Rudolf-Werner Dreier | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>