Featured Research

from universities, journals, and other organizations

Specialised germanium surface as universal protein adapter

Date:
March 8, 2013
Source:
Ruhr-University Bochum
Summary:
Researchers have developed a new method for attaching proteins to the surface of germanium crystals -- for the first time also membrane proteins. This enables time-resolved tracking of the interactions between molecules using infrared spectroscopy in a way that is accurate down to atomic resolution.

Researchers at the Ruhr Universität Bochum have developed a new method for attaching proteins to the surface of germanium crystals -- for the first time also membrane proteins. This enables time-resolved tracking of the interactions between molecules using infrared spectroscopy in a way that is accurate down to atomic resolution. The method is applied in the EU project "Kinetics for Drug Discovery, K4DD," in which scientists explore the interplay of drugs and their interaction partners. With the new technology, the researchers can also study so-called G-protein-coupled receptors, which are the site of action for many drugs.

The team of Prof. Dr. Klaus Gerwert, PD Dr. Carsten Kötting and Jonas Schartner from the Chair of Biophysics reports in the Journal of the American Chemical Society.

Attaching proteins to germanium using electron pair bonds

Using infrared (IR) difference spectroscopy, researchers analyse dynamic processes in proteins. In an earlier study, Bochum's biophysicists already succeeded in binding proteins to germanium surfaces using lipids, thus making them accessible to IR spectroscopy. For this, the researchers shine infrared light into the germanium crystal, which is multiply reflected at its boundary surfaces. Part of the light leaves the crystal and thus reaches the proteins bound to the surface. Previously, the researchers used hydrophilic interactions between the crystal and lipid -- i.e. interactions between polar groups of the molecules -- for the bonding. Now they coupled the proteins via an electron pair bond to the germanium. This kind of bond is more stable and works both for soluble and membrane proteins. "Membrane proteins need a kind of soap as an outer shell, a detergent, which washes off a lipid layer. In contrast, our newly developed surface remains stable," Jonas Schartner says.

Chemical modular system

As in a modular system, the researchers placed various molecular layers, one above the other, on the germanium crystal. First, they produced hydroxyl groups on the germanium surface, each consisting of an oxygen atom and a hydrogen atom. The product is referred to as activated germanium. The next layer was formed by a new kind of triethoxysilanes, a hydrocarbon compound, which the RUB team produced itself. The researchers anchored one end of the triethoxysilanes covalently to the germanium, i.e. via an electron-pair bond. They converted the other end into a protein trap. All the proteins that carry a particular adapter, the His-tag, can be attached to this. "There are already a lot of proteins available with this universal adapter" Carsten Kötting says.

Modifying the germanium surface in a controlled manner

Using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS), the researchers kept track of what happened when stacking the different layers on the germanium crystal. Together with Prof. Dr. Martin Muhler and Bastian Mei from the Laboratory of Industrial Chemistry, the biophysicists were able to accurately determine the atomic composition of the layers with the XPS. Proteins can also be observed on surfaces using other techniques, such as surface plasmon resonance. "With surface plasmon resonance, the gradual modification of the surface is carried out blindly," Jonas Schartner says. "We've observed each modification step live and thus have very good control over the process."

Functional test for the new process successful

A test confirmed that the newly created surface serves its purpose. The researchers equipped the germanium crystal with the switch protein Ras, which plays an important role in carcinogenesis. There they allowed it to interact with a second molecule that switches Ras on and off. These two states -- "on" and "off" -- were reflected in the infrared difference spectra. With the new method, the RUB team thus successfully made a protein interaction visible. In future, drugs and their receptors are to be put to the test. "Using the conventional surface plasmon resonance method, it is only possible to determine whether an interaction takes place. A special feature of our method is that different types of active substance interactions also lead to differences in the difference spectrum," Jörn Güldenhaupt says. "With this additional information, the mechanism of action can be examined much better. This can be critical in the development of active substances."

Project funding

Funding for the project is provided by the Protein Research Department at the RUB, by the state of North Rhine-Westphalia within the framework of the "Center for Vibrational Microscopy" (CVM), the "Innovative Medicines Initiative" (K4DD) and by the Collaborative Research Centre (SFB) 642 "GTP- and ATP-dependent membrane processes," whose spokesperson is Prof. Gerwert.


Story Source:

The above story is based on materials provided by Ruhr-University Bochum. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jonas Schartner, Jörn Güldenhaupt, Bastian Mei, Matthias Roegner, Martin Muhler, Klaus Gerwert, Carsten Kötting. Universal Method for Protein Immobilization on Chemically Functionalized Germanium Investigated by ATR-FTIR Difference Spectroscopy. Journal of the American Chemical Society, 2013; 130215115145001 DOI: 10.1021/ja400253p

Cite This Page:

Ruhr-University Bochum. "Specialised germanium surface as universal protein adapter." ScienceDaily. ScienceDaily, 8 March 2013. <www.sciencedaily.com/releases/2013/03/130308111319.htm>.
Ruhr-University Bochum. (2013, March 8). Specialised germanium surface as universal protein adapter. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2013/03/130308111319.htm
Ruhr-University Bochum. "Specialised germanium surface as universal protein adapter." ScienceDaily. www.sciencedaily.com/releases/2013/03/130308111319.htm (accessed July 26, 2014).

Share This




More Plants & Animals News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How to Make Single Serving Smoothies: Howdini Hacks

How to Make Single Serving Smoothies: Howdini Hacks

Howdini (July 24, 2014) — Smoothies are a great way to get in lots of healthy ingredients, plus they taste great! Howdini has a trick for making the perfect single-size smoothie that will save you time on cleanup too! All you need is a blender and a mason jar. Video provided by Howdini
Powered by NewsLook.com
Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) — An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) — The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) — A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins