Khandelia Himanshu, Jensen Morten Ø, Mouritsen Ole G
MEMPHYS-Center for Biomembrane Physics, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
J Phys Chem B. 2009 Apr 16;113(15):5239-44. doi: 10.1021/jp809152c.
The spinach plant aquaporin SoPIP2;1 is a gated water channel, which switches between open and closed states depending on the conformation of a 20-residue cytoplasmic loop, the D-loop. Using fully atomistic molecular dynamics simulations, we have investigated the possibility of driving the conformational equilibrium of the protein toward a constitutively open state. We introduce two separate mutations in the D-loop, while being in the closed conformation. We show that the single channel permeability of both mutants is comparable to that of the open conformation. This Article provides new molecular insight into the gating mechanism of SoPIP2;1. It is proposed that residues Arg190, Asp191, and Ser36 might play important roles in the gating of the protein.
菠菜植物水通道蛋白SoPIP2;1是一种门控水通道，它根据由20个残基组成的细胞质环（D环）的构象在开放和关闭状态之间切换。我们使用全原子分子动力学模拟，研究了将该蛋白质的构象平衡驱动至组成型开放状态的可能性。在处于关闭构象时，我们在D环中引入了两个单独的突变。我们发现，两个突变体的单通道通透性与开放构象的相当。本文为SoPIP2;1的门控机制提供了新的分子见解。有人提出，精氨酸190、天冬氨酸191和丝氨酸36可能在该蛋白质的门控中发挥重要作用。
