Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tracked step for step: ATP splitting in membrane protein dynamically measured for the first time

11.07.2012
Tracked step for step
ATP splitting in membrane protein dynamically measured for the first time
RUB researchers report in the Journal of Biological Chemistry

How a transport protein obtains its driving force from the energy storage molecule ATP, has been tracked dynamically by RUB researchers. Using time-resolved infrared spectroscopy, they measured the structural changes in the bacterial membrane protein MsbA and its interaction partner ATP.


ATP splitting: The transport protein MsbA (grey) splits ATP (coloured), to generate energy for the transport process. ATP has three phosphate groups (orange-red). If one of them is split off (yellow), energy is released. The splitting process can be tracked in the infrared spectrum (above), in which the various ATP intermediate products leave characteristic bands (red: ATP, yellow: split-off phosphate, white: protein).
Image: Falk Syberg

The researchers led by Prof. Dr. Eckhard Hofmann and Prof. Dr. Klaus Gerwert from the Biophysics Department report on the results in the current issue of the Journal of Biological Chemistry.

Transport proteins are associated with various diseases

ABC transporters are membrane proteins that transport various substances from one side of the cell membrane to the other. The driving force for this is provided by the molecule ATP, a universal energy storage of the cells. ATP has three phosphate groups. If one of these splits off, energy is released. The transporters are of great medical significance as they play a central role in the multi-drug resistance of cancer cells to chemotherapeutic substances and are associated with various inherited diseases like cystic fibrosis.
In recent years, researchers have uncovered the 3D structures of several of these transporters at the atomic level. Although the architecture of the nanomachines is known, a detailed understanding of how the splitting of the energy carrier ATP dynamically enables the transport of various substances across biological membranes has so far been lacking.

Protein controls ATP splitting

The Bochum researchers have now dynamically tracked the ATP splitting, called hydrolysis, for the first time in the fat transporter MsbA from the bacterium Escherichia coli. Using fourier transform infrared spectroscopy, they studied the motor domains of MsbA, i.e. the part of the protein where the ATP splitting takes place. Using this method, researchers can track minute changes in the protein in the range of nanoseconds. Simultaneously, the method also records changes in the molecules the protein interacts with - in this case ATP.

Phosphate signals reveal what happens during the splitting

The big challenge presented by the data analysis is to assign the signals in the measured spectrum to specific molecules or molecular groups. If this is successful, you can see which groups of molecules are structurally changed and when. The biophysicists marked the phosphate groups of the ATP molecule, so that they left characteristic signals in the spectrum. In this way they tracked, how ATP bound to the transport protein, how one of its three phosphate groups split off and was released into the environment without first latching back on to the protein. “Our data also provides important clues as to how the protein moves during ATP hydrolysis. This lays the foundation for the study of the whole membrane protein, which we are going to tackle next”, says Professor Hofmann. The investigations were supported by the Protein Research Department at the RUB and funds of the collaborative research centre SFB 642 “GTP and ATP dependent membrane processes”, whose speaker is Prof. Dr. Klaus Gerwert.

Bibliographic record

F. Syberg, Y. Suveyzdis, C. Kötting, K. Gerwert, E. Hofmann (2012): Time-resolved fourier transform infrared spectroscopy of the nucleotide-binding domain from the ATP-binding cassette transporter MsbA. ATP Hydrolysis is the rate-limiting step in the catalytic cycle, Journal of Biological Chemistry, doi: 10.1074/jbc.M112.359208

Further information

Prof. Dr. Eckhard Hofmann, Protein Crystallography, Faculty of Biology and Biotechnology at the Ruhr-Universität, 44780 Bochum, Germany, tel. +49/234/32-24463, eckhard.hofmann@bph.rub.de

Click for more

Biophysics at the RUB
http://www.bph.ruhr-uni-bochum.de/index_en.htm

Editor: Dr. Julia Weiler

Dr. Josef König | idw
Further information:
http://www.ruhr-uni-bochum.de

More articles from Life Sciences:

nachricht Molecular motors run in unison in a metal-organic framework
20.03.2019 | University of Groningen

nachricht Active substance from plant slows down aggressive eye cancer
20.03.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Molecular motors run in unison in a metal-organic framework

20.03.2019 | Life Sciences

Active substance from plant slows down aggressive eye cancer

20.03.2019 | Life Sciences

Novel sensor system improves reliability of high-temperature humidity measurements

20.03.2019 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>