美国华盛顿大学David Baker小组的最新研究提出了自定义的选择性滤波器几何Ca²⁺通道自下而上的设计。相关论文发表在2025年10月22日出版的《自然》杂志上。

在这里，该课题组描述了一种自下而上的基于RFdifftheions的方法，从定义的选择性过滤器残留物几何形状构建Ca²⁺通道，并将这种方法用于设计具有不同配位数和不同几何形状的Ca²⁺选择性过滤器的对称寡聚通道，这些通道在多个跨膜螺旋支撑的更宽孔入口处。所设计的通道蛋白组装成均匀的含孔颗粒，对于四聚体和六聚体离子配位构型，膜片钳实验表明，所设计的通道对Ca²⁺的电导高于对Na⁺和其他二价离子（Sr²⁺和Mg²⁺）的电导，这些离子在选择性过滤器残基突变后被消除。低温电镜观察结果表明，该设计方法具有较高的精度，六聚体Ca²⁺通道的结构与设计模型基本一致。他们自下而上的设计方法现在可以通过直接构建来测试与过滤器几何形状和离子选择性相关的假设，并为为广泛的应用创建选择性离子通道提供了路线图。

研究人员表示，原生离子通道在生物系统中发挥着关键作用，工程版本的离子通道被广泛用作化学发生工具和传感设备。蛋白质设计已被用于生成含孔的跨膜蛋白质，但由于缺乏以原子级精度放置金属配位残基的方法，具有特定于目标离子的氨基酸侧链精确排列的选择性过滤器（天然离子通道的一个关键特征）的设计一直受到限制。

附：英文原文

Title: Bottom-up design of Ca2+ channels from defined selectivity filter geometry

Author: Liu, Yulai, Weidle, Connor, Mihaljevi, Ljubica, Watson, Joseph L., Li, Zhe, Yu, Le Tracy, Majumder, Sagardip, Borst, Andrew J., Carr, Kenneth D., Kibler, Ryan D., Gamal El-Din, Tamer M., Catterall, William A., Baker, David

Issue&Volume: 2025-10-22

Abstract: Native ion channels play key roles in biological systems, and engineered versions are widely used as chemogenetic tools and in sensing devices1,2. Protein design has been harnessed to generate pore-containing transmembrane proteins, but the design of selectivity filters with precise arrangements of amino acid side chains specific for a target ion, a crucial feature of native ion channels3, has been constrained by the lack of methods for placing the metal-coordinating residues with atomic-level precision. Here we describe a bottom-up RFdiffusion-based approach to construct Ca2+ channels from defined selectivity filter residue geometries, and use this approach to design symmetric oligomeric channels with Ca2+ selectivity filters having different coordination numbers and different geometries at the entrance of a wider pore buttressed by multiple transmembrane helices. The designed channel proteins assemble into homogeneous pore-containing particles and, for both tetrameric and hexameric ion-coordinating configurations, patch-clamp experiments show that the designed channels have higher conductances for Ca2+ than for Na+ and other divalent ions (Sr2+ and Mg2+) that are eliminated after mutation of selectivity filter residues. Cryogenic electron microscopy indicates that the design method has high accuracy: the structure of the hexameric Ca2+ channel is nearly identical to that of the design model. Our bottom-up design approach now enables the testing of hypotheses relating filter geometry to ion selectivity by direct construction, and provides a roadmap for creating selective ion channels for a wide range of applications.

DOI: 10.1038/s41586-025-09646-z

Source: https://www.nature.com/articles/s41586-025-09646-z