Printing proteins as microarrays for high-throughput function determination

Systematic efforts are currently under way to construct defined sets of clo ned genes for high-throughput expression and purification of recombinant pr oteins. To facilitate subsequent studies of protein function, we have devel oped miniaturized assays that accommodate extremely Low sample volumes and enable the rapid, simultaneous processing of thousands of proteins. A high- precision robot designed to manufacture complementary DNA microarrays was u sed to spot proteins onto chemically derivatized glass slides at extremely high spatial densities. The proteins attached covalently to the slide surfa ce yet retained their ability to interact specifically with other proteins, or with small molecules, in solution. Three applications for protein micro arrays were demonstrated: screening for protein-protein interactions, ident ifying the substrates of protein kinases, and identifying the protein targe ts of small molecules.