SARS SPIKE PROTEIN

GWB-F06EAE

SARS SPIKE PROTEIN

This product is specific for the SARS (Severe acute respiratory syndrome) Spike glycoprotein. The Spike protein is a type I membrane protein and functions in adhesion to host cells where it binds to Angiotensin-converting enzyme 2 (ACE2). The amino terminal region folds to a globular shape forming the characteristic spike structure and contains the binding site for ACE2.

Phosphate buffered saline

S1 attaches the virion to the cell membrane by interacting with human ACE2 and CLEC4M/DC-SIGNR initiating the infection. Binding to the receptor and internalization of the virus into the endosomes of the host cell probably induce conformational changes in the S glycoprotein. Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes.

Homotrimer. Binds to human and palm civet ACE2 and human CLEC4M/DC-SIGNR. Interacts with the accessory proteins 3a and 7a.

The KxHxx motif seems to function as an ER retrieval and binds COPI in vitro.

Tor2 is the prototype of the virus isolated during the severe SARS outbreak in 2002-2003. GD03 has been isolated from the second mild SARS outbreak in winter 2003-2004. SZ3 has been isolated from palm civet the presumed animal reservoir. The spike proteins from those three isolates display a strong affinity for palm civet ACE2 receptor whereas only the Tor2 spike protein efficiently binds human ACE2. This may explain the high pathogenicity of Tor2 virus whose spike is highly adapted to the human host. Therefore the lack of severity of disease during the 2003-2004 outbreak could be due to the incomplete adaptation of GD03 virus to bind human ACE2. Mutation Asn-479 and Thr-487 in palm civet coronavirus seems necessary and sufficient for the virus to acquire the ability to efficiently infect humans.