AsianScientist (Jun. 18, 2019) – Researchers in Japan have devised a technique to determine the high-resolution three-dimensional structure of proteins inside living eukaryotic cells. They published their work in the journal Angewante Chemie International Edition.
Eukaryotic cells are the building blocks of a vast range of organisms, including all fungi, plants and animals. Their internal structure is extremely complex and varied, with an intricate structural hierarchy and a vast range of biomacromolecules distributed around a cytoskeletal network. This has made it difficult to see what each protein inside the cells does in its natural environment.
To tackle this challenge, a team of researchers led by Assistant Professor Teppei Ikeya and Professor Yutaka Ito at Tokyo Metropolitan University, Japan, used nuclear magnetic resonance (NMR) spectroscopy to obtain the 3D structure of specific proteins expressed inside sf9 cultured insect cells. These eukaryotic cells are originally derived from a type of moth larva widely used for protein production.
Prior to this study, the team had already succeeded in elucidating high-resolution protein structures inside bacteria, which are non-eukaryotes. However, the same techniques did not fare as well in the sf9 cells due to the significantly lower protein concentrations in them.
Hence, the researchers combined sparse sampling-based rapid NMR measurements with computational methods employing statistical techniques like Bayesian inference. A bioreactor system was also equipped inside the NMR apparatus which kept the cells in a healthy state during the measurements.
With their approach, the team was able to elucidate the 3D structure of three model proteins with unprecedentedly high resolution of 0.05 nanometers, which allowed them to identify the positions of the proteins’ main chain atoms. They also demonstrated that proteins adopt different conformations when inside cells as opposed to when they were freely dispersed in solution.
Hence, the researchers suggest that their method can be used to locate and quantify structural changes of proteins in an intracellular environment, with implications for biomedical research.
The article can be found at: Tanaka et al. (2019) High‐Resolution Protein 3D Structure Determination in Living Eukaryotic Cells.
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Source: Tokyo Metropolitan University.
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