1.A.77.1.15
MCU of 488 aas and 2 TMSs.  The 3.8 Å cryoEM structure has been solved (Nguyen et al. 2018). The channel is a homotetramer with two-fold symmetry in its amino-terminal domain (NTD) that adopts a structure similar to that of human MCU. The NTD assembles as a dimer of dimers to form a tetrameric ring that connects to the transmembrane domain through an elongated coiled-coil domain. The ion-conducting pore domain maintains four-fold symmetry, with the selectivity filter positioned at the start of the pore-forming TM2 helix. The aspartate and glutamate sidechains of the conserved DIME motif are oriented towards the central axis and separated by one helical turn (Nguyen et al. 2018).