Preparation of protein arrays using cell-free protein expression

Protein microarrays are a miniaturized format for assaying functional protein interactions and proteomics using a high-throughput, multiplexed approach. The primary limitations of this technology include the time and cost involved in the production of highly purified individual proteins for arraying and also the limited stability of functional proteins once arrayed. In light of these difficulties, cell-free protein expression systems are being increasingly used to generate protein arrays in situ from coding DNA sequences. This chapter describes the method DNA array to protein array (DAPA) allowing the repeated "printing" of protein arrays directly from a DNA array template using cell-free protein expression. Once the DNA templates have been spotted, the generation of the protein array involves only simple handling procedures and is relatively time and cost-efficient, and protein arrays can easily be produced "on demand" as and when required. The resultant protein array may be used for any downstream applications as for conventionally spotted protein arrays.