Structural models for the KCNQ1 voltage-gated potassium channel

Area of Science:

• Structural biology
• Molecular biophysics
• Ion channel research

Background:

• Mutations in the human voltage-gated potassium channel KCNQ1 are linked to deafness and cardiac arrhythmias like congenital long QT syndrome.
• Understanding the structural basis of KCNQ1 mutations is crucial for explaining disease phenotypes.

Purpose of the Study:

• To develop 3-D structural models of the open and closed states of the human KCNQ1 channel.
• To facilitate structure-based hypotheses for mutation-phenotype relationships.

Main Methods:

• Modeled the KCNQ1 open state using Rosetta and Molecular Operating Environment, referencing the rat Kv1.2 open state structure.
• Developed the KCNQ1 closed state model based on bacterial potassium channel crystal structures and a Kv1.2 closed state model.
• Generated a database of over 85 disease-linked KCNQ1 mutation sites and predicted residue-residue interactions in both states.

Main Results:

• Created 3-D structural models for both open and closed states of the human KCNQ1 channel.
• Compiled a database detailing mutation locations and predicted interactions for over 85 disease-associated sites.
• Identified a common interface in the open state model for gain-of-function KCNQ1 mutations, involving voltage sensor and pore helix regions.

Conclusions:

• The developed KCNQ1 models and database provide a platform for generating structure-based hypotheses for disease phenotypes.
• A critical interface in the open channel state, involving specific subunit interactions, appears vital for KCNQ1 channel gating.
• These findings offer new insights into the molecular mechanisms underlying KCNQ1 channelopathies.