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by Eric Martz
After decades of slow progress by many groups, in 2020, AlphaFold2 proved able to accurately predict the detailed structures of two-thirds of single protein domains from their amino acid sequences. Pictured is AlphaFold2's prediction for the ORF8 protein of SARS-CoV-2 (black), compared with a subsequently published X-ray crystallographic structure (colors). ORF8 contributes to virulence in COVID-19.
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F Wang, Y Gu, JP O'Brien, SM Yi, SE Yalcin, V Srikanth, C Shen, D Vu, NL Ing, AI Hochbaum, EH Egelman, NS Malvankar. Cell 2019 doi: 10.1016/j.cell.2019.03.029
Bacteria living in anaerobic environments (no oxygen) need alternative electron acceptors in order to get energy from their food. An acceptor abundant in the earth's crust is red iron oxide ("rust"), which gets reduced to black iron oxide (magnetite). Many bacteria, such as Geobacter, get their metabolic energy by transferring electrons to acceptors that are multiple cell diameters distant, using protein nanowires. These were long thought to be pili. But when the structure of the nanowires was solved in 2019, to everyone's surprise, they turned out to be unprecedented linear polymers of multi-heme cytochromes. The hemes form an electrically conductive chain in the cores of these nanowires.

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Above is an integral membrane protein that takes up, into your intestinal cells, orally consumed peptide nutrients and drugs. Its lumen-face (top) opens and binds peptide or drug (small solid object in the center), then closes, while its cytoplasmic face (bottom) opens to release its cargo into the intestinal cell, which passes it on to the blood circulation.

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