Protein crystallization benefits from the rough well surface of a 48-well polystyrene microplate

It’s not clear whether the drop well surface can induce heterogeneous nucleation to increase the probability of screening success, although a medium-throughput 48-well SBS (the Society for Biomolecular Screening, USA) polystyrene microplate has been widely used for protein crystallization screening. Here, our accumulating data suggested that this 48-well SBS microplate with rough surface is beneficial for protein crystallization. It was observed that some protein crystals were only formed on the rough edges and/or walls of the drop well, but not on the flat bottom or in the crystallization drop. It was further demonstrated with two standard test proteins. The protuberances, grooves and cavities with varied sizes and shapes at micrometer-scale in the rough drop well wall can serve as nucleants and induce heterogeneous nucleation of protein crystals. The rough wall microplate provides a potent tool for protein crystallographers embarking on crystallization trials.