Wehrspan Zachary J, McDonnell Robert T, Elcock Adrian H
Department of Biochemistry, University of Iowa, Iowa City, IA, USA.
Department of Biochemistry, University of Iowa, Iowa City, IA, USA.
J Mol Biol. 2022 Jan 30;434(2):167377. doi: 10.1016/j.jmb.2021.167377. Epub 2021 Nov 24.
DeepMind's AlphaFold2 software has ushered in a revolution in high quality, 3D protein structure prediction. In very recent work by the DeepMind team, structure predictions have been made for entire proteomes of twenty-one organisms, with >360,000 structures made available for download. Here we show that thousands of novel binding sites for iron-sulfur (Fe-S) clusters and zinc (Zn) ions can be identified within these predicted structures by exhaustive enumeration of all potential ligand-binding orientations. We demonstrate that AlphaFold2 routinely makes highly specific predictions of ligand binding sites: for example, binding sites that are comprised exclusively of four cysteine sidechains fall into three clusters, representing binding sites for 4Fe-4S clusters, 2Fe-2S clusters, or individual Zn ions. We show further: (a) that the majority of known Fe-S cluster and Zn binding sites documented in UniProt are recovered by the AlphaFold2 structures, (b) that there are occasional disputes between AlphaFold2 and UniProt with AlphaFold2 predicting highly plausible alternative binding sites, (c) that the Fe-S cluster binding sites that we identify in E. coli agree well with previous bioinformatics predictions, (d) that cysteines predicted here to be part of ligand binding sites show little overlap with those shown via chemoproteomics techniques to be highly reactive, and (e) that AlphaFold2 occasionally appears to build erroneous disulfide bonds between cysteines that should instead coordinate a ligand. These results suggest that AlphaFold2 could be an important tool for the functional annotation of proteomes, and the methodology presented here is likely to be useful for predicting other ligand-binding sites.
DeepMind公司的AlphaFold2软件在高质量的三维蛋白质结构预测方面引发了一场革命。在DeepMind团队最近的工作中,已经对21种生物体的整个蛋白质组进行了结构预测,有超过360,000个结构可供下载。在此我们表明,通过详尽列举所有潜在的配体结合方向,可以在这些预测结构中识别出数千个铁硫(Fe-S)簇和锌(Zn)离子的新结合位点。我们证明AlphaFold2通常能对配体结合位点做出高度特异性的预测:例如,仅由四个半胱氨酸侧链组成的结合位点可分为三类,分别代表4Fe-4S簇、2Fe-2S簇或单个Zn离子的结合位点。我们进一步表明:(a)AlphaFold2结构能够找回UniProt中记录的大多数已知Fe-S簇和Zn结合位点;(b)AlphaFold2与UniProt之间偶尔存在争议,AlphaFold2会预测出高度合理的替代结合位点;(c)我们在大肠杆菌中识别出的Fe-S簇结合位点与先前的生物信息学预测结果吻合良好;(d)此处预测为配体结合位点一部分的半胱氨酸与通过化学蛋白质组学技术显示具有高反应性的半胱氨酸几乎没有重叠;(e)AlphaFold2偶尔似乎会在本应配位配体而不是形成二硫键的半胱氨酸之间构建错误的二硫键。这些结果表明,AlphaFold2可能是蛋白质组功能注释的重要工具,本文介绍的方法可能有助于预测其他配体结合位点。