1.A.84.1.9
Killifish CALHM1 of 351 aas and 5 TMSs in a 2 + 2 + 1 TMS arrangement.  The cryoEM structure has been determined to 2.66 Å resolution (Demura et al. 2020).  The human CALHM-2 (CALMH2) and the C. elegans CLHM-1 (CLHM1) were also solved at lower resolution. The CALHM1 octameric structure reveals that the N-terminal helix forms the constriction site at the channel pore in the open state and modulates the ATP conductance. The CALHM2 undecamer and CLHM-1 nonamer structures show the different oligomeric stoichiometries among CALHM homologs. The cryo-EM structures of the chimeric construct revealed that the intersubunit interactions in the transmembrane region and the TMS-intracellular domain linker define the oligomeric stoichiometry (Demura et al. 2020).