收录解读
问题与背景：金属水解酶能够催化生物体系中最困难的一类水解反应，但从头设计高活性金属酶一直非常困难，过去往往活性偏低、需要大量定向进化补救。论文聚焦的核心问题是：能否直接从计算设计出具有真实高催化效率的 metallohydrolases，而不是停留在概念验证层面。
方法/新意：作者引入 RFdiffusion2，从量子化学推导的活性位几何出发进行催化位点支架化设计，不再要求先指定每个催化残基的序列位置和主链坐标。论文最强的部分不只是算法更新，而是把该设计流程真正用于锌依赖 metallohydrolases，并在实验上得到远高于既往设计结果的催化效率。
意义/放在仓库中的位置：这篇工作适合放在 AI x biology / protein design 主线，而且是高位条目。它显示生成式结构设计已经不只是做结合蛋白或简单酶，而是开始进入复杂金属酶活性位设计，这对计算酶工程、环境降解催化及更广泛的功能蛋白设计都有明显外溢性。
局限/为何不再升一级：它已经是很强的颠覆性工作，但是否达到更高一级，还取决于这种设计范式在更广酶类和更复杂反应上的可扩展性，以及社区是否将其视为新的默认设计路径。目前更稳妥的定位仍是颠覆性。
原始摘要
De novo enzyme design seeks to build proteins containing ideal active sites with catalytic residues surrounding and stabilizing the transition state(s) of the target chemical reaction . The generative artificial intelligence method RFdiffusion solves this problem, but requires specifying both the sequence position and backbone coordinates for each catalytic residue, limiting sampling. Here we introduce RFdiffusion2, which eliminates these requirements, and use it to design zinc metallohydrolases starting from quantum chemistry-derived active site geometries. From an initial set of 96 designs tested experimentally, the most active has a catalytic efficiency ( k cat / K M ) of 16,000 M s , orders of magnitude higher than previously designed metallohydrolases . A second round of 96 designs yielded 3 additional highly active enzymes, with k cat / K M values of up to 53,000 M s and a catalytic rate constant ( k cat ) of up to 1.5 s . The design models of the four most active designs differ from known structures and from each other, and the crystal structure of the most active design is very close to the design model, demonstrating the accuracy of the design method. The most active enzymes are predicted by PLACER and Chai-1 (ref. ) to have preorganized active sites that effectively position the substrate for nucleophilic attack by a water molecule activated by the bound metal. The ability to generate highly active enzymes directly from the computer, without experimental optimization, should enable a new generation of potent designer catalysts .