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Updated: Aug 14, 2026
Engineering Antiviral Agents via Surface Plasmon Resonance
Published on: June 14, 2022
Solution structure of the X4 protein coded by the SARS related coronavirus reveals an immunoglobulin like fold and
Karen Hänel1, Thomas Stangler, Matthias Stoldt
1Forschungszentrum Jülich, Institut für Biologische Informationsverarbeitung (IBI-2), Germany.
Abstract:
The SARS related Coronavirus genome contains a variety of novel accessory genes. One of these, called ORF7a or ORF8, code for a protein, known as 7a, U122 or X4. We set out to determine the three-dimensional structure of the soluble ectodomain of this type-I transmembrane protein by nuclear magnetic resonance spectroscopy. The fold of the protein is the first member of a further variation of the immunoglobulin like beta-sandwich fold. Because X4 does not reveal significant sequence homologies to proteins in the data bases, we carried out a structure based similarity search for proteins with known function. High structural similarity to Dl domains of ICAM-1 and ICAM-2, and common features in amino acid sequence between X4 and ICAM-1, suggest X4 to possess binding activity for the alpha(L) integrin I domain of LFA-1. Further, based on this structure based prediction, potential functions of X4 in virus replication and pathogenesis are discussed.
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