Direct Production and Purification of T7 Phage Display Cloned Proteins Selected and Analyzed on Microarrays

Phage display technology has emerged into a powerful tool for identifying proteins with specific binding properties. This technology adds amino acid sequences to the carboxy terminus of a phage capsid protein, thus generating a fusion protein displayed on the surface of the phage. Here, we have developed a high-throughput strategy to synthesize purified protein that solves many of the problems associated with crude phage lysates. Phage DNA was used as a template for a nested PCR that added the T7 promoter, ribosome binding site, and a His6-tag. The PCR product was then used as a template for in vitro transcription/translation. The resulting His6-tagged recombinant protein was then purified by nickel affinity chromatography. The functionality of the purified protein was verified using protein microarray analysis.