Protein engineering involves generating and screening large numbers of variants for desired properties. While modern DNA technology has made it easy to create protein diversity on the DNA level, the selection and validation of candidate proteins from large libraries remains a challenge. We built a screening platform that integrates high-quality fluorescence-based image analysis and robotic picking of bacterial colonies. It allows tracking each individual colony in a large population and collecting quantitative information on library composition during the protein evolution process. We demonstrate the power of the screening platform by optimizing a dim far-red-emitting fluorescent protein whose brightness increased several fold using iterative cycles of mutagenesis and platform-based screening. The resulting protein variant mCarmine is useful for imaging cells and structures within live tissue as well as for molecular tagging. Overall, the platform presented provides powerful, flexible, and low-cost instrumentation to accelerate many fluorescence-based protein optimization projects.

中文翻译：

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基于成像的筛选平台有助于蛋白质工程

蛋白质工程涉及产生和筛选大量具有所需特性的变体。尽管现代DNA技术使在DNA水平上创建蛋白质多样性变得容易，但是从大型文库中选择和验证候选蛋白质仍然是一个挑战。我们构建了一个筛选平台，该平台整合了基于荧光的高质量图像分析和细菌菌落的自动拣选。它允许追踪大批种群中的每个菌落，并在蛋白质进化过程中收集有关文库组成的定量信息。我们通过优化暗淡的远红色发射荧光蛋白展示了筛选平台的功能，该蛋白的亮度使用诱变和基于平台的筛选的迭代循环提高了几倍。所得的蛋白质变体mCarmine可用于对活组织内的细胞和结构进行成像，以及用于分子标记。总体而言，所展示的平台可提供功能强大，灵活且低成本的仪器，以加速许多基于荧光的蛋白质优化项目。