Dynowski Marek, Mayer Maria, Moran Oscar, Ludewig Uwe
Zentrum für Molekularbiologie der Pflanzen, Pflanzenphysiologie, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
FEBS Lett. 2008 Jul 9;582(16):2458-62. doi: 10.1016/j.febslet.2008.06.012. Epub 2008 Jun 17.
Aquaporins and/or aquaglyceroporins regulate the permeability of plant membranes to water and small, uncharged molecules. Using molecular simulations with a plant plasma membrane aquaporin tetramer, the residues in the channel constriction region were identified as the crucial determinants of ammonia and urea conductance. The impact of these residues was experimentally verified using AtPIP2;1 pore mutants. Several, but not all, mutants with a NIP-like selectivity filter promoted yeast growth on urea or ammonia as sole sources of nitrogen. TIP-like mutants conducted urea but not NH(3), and a residue without direct contact to the pore lumen was critical for conduction in the mutants.
水通道蛋白和/或水甘油通道蛋白调节植物膜对水以及不带电荷的小分子的通透性。通过对植物质膜水通道蛋白四聚体进行分子模拟，通道狭窄区域的残基被确定为氨和尿素传导的关键决定因素。使用AtPIP2;1孔突变体通过实验验证了这些残基的影响。几个（但不是全部）具有NIP样选择性过滤器的突变体促进酵母在尿素或氨作为唯一氮源的情况下生长。TIP样突变体传导尿素但不传导NH₃，并且一个与孔腔没有直接接触的残基对于突变体中的传导至关重要。
