Scientists discover green light key for nano assembly
Organisation of life requires protein-based nanostructures, which in turn are arranged in a precise manner to determine their specific functions. Researchers at Ludwig Maximilian University of Munich (LMU) in Germany discovered that using green light enabled them to install single protein molecules at their site of operation with nanometre precision, resulting in the assembly of novel biomolecular machines. Their finding was presented in the Journal of the American Chemical Society. By using the fine tip of the atomic force microscope (AFM), the researchers picked up individual biomolecules and deposited them elsewhere with nanometre accuracy. Called 'Single-molecule cut & paste' (SMC&P), the team first used the technique on deoxyribonucleic acid (DNA) molecules. What prompted them to use it on proteins was the fact that molecular machines responsible for most biochemical processes in cells are composed of proteins, and the controlled assembly of such devices is one of the top objectives of nanotechnology. Led by Professor Hermann Gaub at LMU, the team said its use would give people a greater understanding of what goes on inside living cells, and help the development, construction and use of designer nanomachines. Thanks to this technique, the researchers altered the method, which in turn enabled them to move proteins from a storage site to a specific location with nanometre precision. 'In liquid medium at room temperature, the "weather conditions" at the nanoscale are comparable to those in a hurricane,' said lead author Mathias Strackharn from LMU. Therefore, it is important to firmly attach and then securely hold the molecules to the tip of the AFM when moving them to the construction area. According to the researchers, the forces that tether the proteins when being manipulated and assembled must also be weak enough to ensure they are not damaged, and must be tightly controlled. The team met the study's objectives by using a combination of antibodies, DNA-binding 'zinc-finger' proteins, and DNA anchors. 'We demonstrated the method's feasibility by bringing hundreds of fluorescent GFP [green fluorescent protein] molecules together to form a little green man, like the traffic-light figure that signals to pedestrians to cross the road, but only some micrometres high,' Mr Strackharn explained. This technique can directly test functional aspects of complex protein machines, including how combinations of various enzymes interact and how close together they should be to perform coupled reactions. 'If we can efficiently build mimics of these "enzymatic assembly lines" by bringing individual proteins together, we could perhaps make a significant contribution to the exploitation of sustainable energy sources,' he said.For more information, please visit: Ludwig Maximilian University of Munich (LMU):http://www.en.uni-muenchen.de/index.htmlJournal of the American Chemical Society:http://pubs.acs.org/journal/jacsat
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