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, despite the obvious biomedical benefits of knowing e.g. how a particular protein reacts when cells are subjected to chemical stimuli, like pharmaceutical drugs.
To tackle this challenge, a team from Tokyo Metropolitan University led by Assistant Professor Teppei Ikeya and Professor Yutaka Ito applied nuclear magnetic resonance (NMR) spectroscopy measurements to specific proteins expressed inside sf9 cultured insect cells, a strain of cells originally derived from a type of moth larva widely used for protein production. The team's pioneering NMR work had already succeeded in elucidating high-resolution protein structures inside bacteria (non-eukaryotes). The problem with simply applying the same techniques to proteins in sf9 cells was the significantly lower concentration of target proteins and short lifetime of cells, making it difficult to collect high quality multi-dimensional NMR spectra for nuclear Overhauser effect spectroscopy (NOESY) which would give precise information about how different atoms are spaced inside individual molecules. Thus, they combined a sparse sampling-based rapid NMR measurement scheme with state-of-the-art computational methods employing statistical techniques like Bayesian inference, methods tailored to elucidate protein structures efficiently based on a limited amount of structural information from in-cell NMR spectra with inherently low-sensitivity. A bioreactor system was...
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One of the countries we liberated was Russia, too bad it seems to have cost us our liberty.