Structural mechanism for modulation of synaptic neuroligin-neurexin signaling by MDGA proteins by Elegheert, J, Cvetkovska, V, Clayton, AJ, Heroven, C, Vennekens, KM, Smukowski, SN, Regan, MC, Jia, W, Smith, AC, Furukawa, H, Savas, JN, de Wit, J, Begbie, J, Craig, AM, Aricescu, AR