Structure and intracellular targeting of the SARS-coronavirus Orf7a accessory protein.
Nelson, C.A., Pekosz, A., Lee, C.A., Diamond, M.S., Fremont, D.H.(2005) Structure 13: 75-85
- PubMed: 15642263 
- DOI: https://doi.org/10.1016/j.str.2004.10.010
- Primary Citation of Related Structures:  
1XAK - PubMed Abstract: 
The open reading frame (ORF) 7a of the SARS-associated coronavirus (SARS-CoV) encodes a unique type I transmembrane protein of unknown function. We have determined the 1.8 A resolution crystal structure of the N-terminal ectodomain of orf7a, revealing a compact seven-stranded beta sandwich unexpectedly similar in fold and topology to members of the Ig superfamily. We also demonstrate that, in SARS-CoV- infected cells, the orf7a protein is expressed and retained intracellularly. Confocal microscopy studies using orf7a and orf7a/CD4 chimeras implicate the short cytoplasmic tail and transmembrane domain in trafficking of the protein within the endoplasmic reticulum and Golgi network. Taken together, our findings provide a structural and cellular framework in which to explore the role of orf7a in SARS-CoV pathogenesis.
Organizational Affiliation: 
Department of Pathology and Immunology, 660 South Euclid Avenue, St. Louis, Missouri 63110, USA.