Protein microarrays printed from DNA microarrays.

Protein arrays are miniaturised and highly parallelised formats of interaction-based functional protein assays. Major bottlenecks in protein microarraying are the limited availability and high cost of purified, functional proteins for immobilisation and the limited stability of immobilised proteins in their functional state. In contrast, protein-coding DNA is readily available by PCR, and DNA arrays can be stored over prolonged times without deterioration. This chapter presents a method for the rapid and economical "printing" of replicate protein microarrays directly from a single DNA array template using cell-free protein synthesis, termed "DNA array to protein array," DAPA. The procedure is a truly enabling technology, making customised protein microarrays affordable for laboratories with no access to routine microarray spotting. The experimental effort involved for the printing of a protein array from the template DNA array is comparable to the assembly of a Western blot.