Water and potassium dynamics inside the KcsA K+ channel

FEBS Letters

Guidoni, Leonardo¹  Torre, Vincent¹  Carloni, Paolo¹ 

[1] Istituto Nazionale per la Fisica della Materia (INFM), Italy and International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy

关键词: KcsA;    Potassium channel;    Potassium ion;    Molecular dynamics;    Streptomyces lividans;    MD;    molecular dynamics;    2K;    model with two potassium ions;    3K;    model with three potassium ions;    rmsd;    root mean square displacement;   

DOI  :  10.1016/S0014-5793(00)01712-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Molecular dynamics simulations and electrostatic modeling are used to investigate structural and dynamical properties of the potassium ions and of water molecules inside the KcsA channel immersed in a membrane-mimetic environment. Two potassium ions, initially located in the selectivity filter binding sites, maintain their position during 2 ns of dynamics. A third potassium ion is very mobile in the water-filled cavity. The protein appears engineered so as to polarize water molecules inside the channel cavity. The resulting water induced dipole and the positively charged potassium ion within the cavity are the key ingredients for stabilizing the two K⁺ ions in the binding sites. These two ions experience single file movements upon removal of the potassium in the cavity, confirming the role of the latter in ion transport through the channel.

【 授权许可】

Unknown