Biochemical analysis of coronavirus spike glycoprotein conformational intermediates 1 during membrane fusion 2 3 Miyuki Kawasea, Michiyo Kataokab, Kazuya Shiratoa, and Shutoku Matsuyamaa* 4 5 aDepartment of Virology III, National Institute of Infectious Diseases, Murayama Branch, 4- 6 7-1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan 7 bDepartment of Pathology, National Institute of Infectious Diseases, Murayama Branch, 4-7- 8 1 Gakuen, Musashi-murayama, Tokyo 208-0011, Japan 9 10 Running title: Coronavirus spike activation 11 12 *Address correspondence to