Single-particle cryo-EM studies of a 200 kDa magnesium ion channel reveal large structural changes upon gating, Matthies, Doreen; Dalmas, Olivier; Borgnia, Mario J.; Dominik, Pawel K.; Merk, Alan; Rao, Prashant; Reddy, Bharat G.; Islam, Shahidul; Bartesaghi, Alberto; Perozo, Eduardo; Subramaniam, Sriram