Screening for Protein Activity Using Cell-Free Expression

The analysis of functional protein typically requires lengthy laborious cell based protein expression that can be complicated by the lack of stability or solubility of the purified protein. Cell free protein expression eliminates the requirement for cell culture thus providing quick access to the protein of interest (1).

The HaloTag® Technology provides efficient, covalent and oriented protein immobilization of the fusion protein to solid surfaces (2).

A recent publication demonstrated the feasibility of using cell free expression and the HaloTag technology to express and capture a fusion protein for the rapid screening of protein kinase activity (3). The catalytic subunit of human cAMP dependent protein kinase was expressed in a variety of cell free expression formats as a HaloTag fusion protein. The immobilized cPKA fusion protein was assayed directly on magnetic beads in the active form and was shown to be inhibited by known PKA inhibitory compounds.

Therefore this unique combination of protein expression and capture technologies can greatly facilitate the process of activity screening and characterization of potential inhibitors

References
ResearchBlogging.org

  1. Zhao, K.Q. et al. (2007) Functional protein expression from a DNA based wheat germ cell-free system. J. Struc. Funct. Genomics. 8, 199-208.
  2. Los, G.V. and Wood, K. (2007) The HaloTag: A novel technology for cell imaging and protein analysis. Meth. Mol. Biol. 356, 195-208
  3. Leippe DM, Zhao KQ, Hsiao K, & Slater MR (2010). Cell-free expression of protein kinase a for rapid activity assays. Analytical chemistry insights, 5, 25-36 PMID: 20520741
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    Gary Kobs

    Strategic Marketing Manager at Promega Corporation
    Gary earned his B.S. in Bacteriology, UW-Madison in 1982. From 1982–1986 he served as Research Tech at UW-Madison. From 1986 to the present Gary has been with Promega Corporation serving in many capacities including as the very first editor of Promega Notes. He was also Manager Tech Services and Training, Product Manager Restriction/Modifying Enzymes, Product Manager Protein Analysis, and is now Marketing Manager Protein Analysis.

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