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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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IB Tomasic, MC Metcalf, AI Guce, NE Clark, SC Garman. J. Biol. Chem. 2010 doi: 10.1074/jbc.M110.118588
The human lysosomal enzymes α-galactosidase and α-N-acetylgalactosaminidase share 46% amino acid sequence identity and have similar folds. Using a rational protein engineering approach, we interconverted the enzymatic specificity of α-GAL and α-NAGAL. The engineered α-GAL retains the antigenicity but has acquired the enzymatic specificity of α-NAGAL. Conversely, the engineered α-NAGAL retains the antigenicity but has acquired the enzymatic specificity of the α-GAL enzyme. Comparison of the crystal structures of the designed enzyme to the wild-type enzymes shows that active sites superimpose well, indicating success of the rational design. The designed enzymes might be useful as non-immunogenic alternatives in enzyme replacement therapy for treatment of lysosomal storage disorders such as Fabry disease.

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Touching stretches cell membranes, opening mechanosensitive ion channels, leading to sensation by the nervous system. Pictured is the transmembrane region of a similar channel in bacteria. When closed, the narrow opening is lined by hydrophobic amino acid sidechains, making it non-conductive to ions.

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