Fig. 4: Structural features of the VSDs of NALCN.
From: Structure of the human sodium leak channel NALCN in complex with FAM155A
a Structure-based sequence alignment of the four VSDs. The boundaries for the S1 to S4 segments are shaded gray. The gating charges (GCs) in the S4 helices are colored red. The residues that correspond to the charge transfer center (CTC) on S2 and S3 helices as well as the polar or acidic residues on S1 that coordinate GCs are highlighted in blue. b All four VSDs adopt up or depolarized state. The four VSDs are superimposed relative to CTC and An1 on S2. For visual clarity, the S1 segments are omitted. c Structural details of each VSD. The GCs, CTCs, and the polar or acidic residues participating in GC coordination are shown in sticks. The GCs are labeled in red. The S4-5I loop and non-conserved aromatic residues in the CTC of repeat III are highlighted by red circles. The short 310 helix turn in repeat IV is indicated by a dark green line.
