1 (1) 6 Chains: A, B, C, D, E, F (2) (3) K (4) K2 2 D.A.DOYLE, J.M.CABRAL, R.A.PFUETZNER, A.KUO, J.M.GULBIS, S.L.COHEN, B.T.CHAIT, R.MACKINNON 3 (1) 1MNM (2) 3 (3) (4) Spin Spin off protein electron Spacefill ribbon Strands Cartoon