Fig. 1: Kv3.1a full-length structure showing alternative T1 arrangement compared to Kv1.2/2.1 and electrostatic ATM/T1 interactions.
From: Cryo-EM structure of the human Kv3.1 channel reveals gating control by the cytoplasmic T1 domain
a Density maps of the human Kv3.1a channel, coloured by chain. TM region is illustrated by dashed lines. b Superposition of a single chain of Kv3.1a (dark blue cartoon) with one protomer of the Kv1.2-2.1 paddle chimera (pdb: 6EBK, shown in yellow cartoon representation), aligning the S4/S5 linker and pore domain. c Cytoplasmic view of the T1 domain of Kv3.1a superposed on the Kv1.2/2.1 structure (yellow cartoon) using the same alignment as in (b). Angle indicates rotational displacement measured between a vector defined by cα atoms of G16/H22 in Kv3.1 and G41/Q47 in Kv1.2-2.1, respectively. d Superposition of an individual T1 protomer (residues 8–120, dark blue) from Kv3.1 with the respective region of the Kv1.2-2.1 protomer (yellow). e Detailed view of the ATM/T1 contact region. T1 is shown as semi-transparent surface representation/cartoon and the ATM motif C-terminal from S6T is shown as red cartoon. f Close-up view of the inset from e, illustrating electrostatic contacts between acidic residues in α5 of the N-terminal T1 domain and a cluster of lysines (K454–K458) within the ATM of the C-terminus. Red frame indicates location of frameshift variant K457fs associated with EPM7 (ClinVar ID: 692088).
