CRISPR-Cas systems employ ribonucleoprotein complexes to identify nucleic acid targets with complementarity to bound CRISPR RNAs. Analyses of the high diversification of these effector complexes suggest that they can exhibit a wide spectrum of target requirements and binding affinities. Therefore, streamlined analysis techniques to study the interactions between nucleic acids and proteins are necessary to facilitate the characterization and comparison of CRISPR-Cas effector activities. Bio-layer Interferometry (BLI) is a technique that measures the interference pattern of white light that is reflected from a layer of biomolecules immobilized on the surface of a sensor tip (bio-layers) in real time and in solution. As streptavidin-coated sensors and biotinylated oligonucleotides are commercially available, this method enables straightforward measurements of the interaction of CRISPR-Cas complexes with different targets in a qualitative and quantitative fashion. Here, we present a general method to carry out binding assays with the Type I-Fv complex from Shewanella putrefaciens and the Type I-F complex from Shewanella baltica as model effectors. We report target specificities, dissociation constants and interactions with the Anti-CRISPR protein AcrF7 to highlight possible applications of this technique.

CRISPR-Cas系统使用核糖核蛋白复合物来鉴定与结合的CRISPR RNA具有互补性的核酸靶标。这些效应物复合物的高度多样化的分析表明，它们可以表现出广泛的靶标要求和结合亲和力。因此，研究核酸和蛋白质之间相互作用的简化分析技术对于促进CRISPR-Cas效应子活性的表征和比较是必要的。生物层干涉法（BLI）是一种实时测量溶液中固定在传感器尖端（生物层）表面的生物分子层反射的白光干涉图案的技术。由于涂有链霉亲和素的传感器和生物素化的寡核苷酸是可商购的，这种方法能够以定性和定量的方式直接测量CRISPR-Cas复合物与不同靶标的相互作用。在这里，我们提出了一种通用的方法来进行与I-Fv型复合物的结合测定腐烂希瓦氏菌 以及来自 波罗的海希瓦氏菌作为模型效应器。我们报告了靶标特异性，解离常数以及与抗CRISPR蛋白AcrF7的相互作用，以突出该技术的可能应用。