New Automated Systems for Size-fractionation of Protein Samples

Sage Science has developed two new systems for automated preparative electrophoresis of protein samples. In both systems, the user simply loads samples into precast gel cassettes, programs the desired collection ranges into instrument software, and starts the run. At run completion, the user removes the desired protein fraction(s) from membrane-bounded elution modules within the cassette. The fractionated samples are recovered in SDS gel buffer – no gel extraction is required. Instrument software controls of timing of protein fractionation using input from on-board optical detection units, which monitor the progress of fluorescently-labeled molecular weight markers during electrophoresis. The two system differ significantly in fractionation strategy. The first system is based on Sage's existing BluePippin electrophoresis instrument for nucleic acid fractionation, but features precast gel cassettes developed specifically for protein fractionation. The protein BluePippin cassettes are useful for collecting one or two targeted protein fractions from a sample. The second system, the Sage ELF system (for Electrophoretic Lateral Frationator), is a completely new instrument/cassette system designed to fractionate a protein sample into 12 contiguous size fractions. In both systems, SDS agarose gels are used as the separation matrix, and fractionated proteins recovered in SDS gel buffer. 5% agarose gels are used for proteins 18 to 80 kd in size, and 3% agarose gels are used for sample 50-200 kb in size. The width of the size collection window can be varied by the user, with a minimum window of about 20 kd. The new Sage systems should provide increased reproducibility and ease-of-use for procedures that require gel isolation of proteins, such as top-down proteomics studies and other protein mass spectrometry methods.