Recent studies have begun to reveal the structure of the coronavirus pre-fusion spike , N protein (Chen et al., 2007; Fan et al., 2005; Huang et al., 2004; Jayaram et al., 2006; Saikatendu et al., 2007; Schutze et al., 2006) , the hemagglutinin-esterase protein, which is found on some group 2 coronaviruses (Zeng et al., 2008) , and the E protein (Pervushin et al., 2009) .