Investigating Structural Dynamics of KCNE3 in Different Membrane Environments Using Molecular Dynamics Simulations

Area of Science:

• Biophysics
• Computational Biology
• Membrane Protein Dynamics

Background:

• KCNE3 is a vital potassium channel accessory protein involved in potassium ion recycling, particularly with KCNQ1.
• Found in the small intestine, colon, and heart, KCNE3's structural dynamics in native membranes are not well understood.

Purpose of the Study:

• To characterize the molecular motions and interactions of KCNE3 within native-like lipid bilayer environments.
• To investigate the conformational dynamics of KCNE3 using all-atom molecular dynamics simulations.

Main Methods:

• All-atom molecular dynamics (MD) simulations were employed.
• KCNE3 was simulated in three distinct lipid bilayer compositions: POPC/POPG (3:1), POPC alone, and DMPC alone.

Main Results:

• The transmembrane domain (TMD) of KCNE3 exhibited greater stability and less flexibility compared to its N- and C-termini across all simulated membrane environments.
• The flexibility of the N- and C-termini of KCNE3 varied depending on the specific lipid composition.
• Residue A69 was located near the center of the lipid bilayers, with residues S57 and S82 positioned near the membrane surfaces, consistent with spanning the membrane.

Conclusions:

• MD simulations reveal distinct flexibility profiles for KCNE3 domains within different membrane environments.
• These findings provide a detailed molecular understanding of KCNE3 structural dynamics, complementing existing experimental data.
• The results will aid in designing future biophysical experiments to further elucidate KCNE3 function in native settings.