Progress in computer design methods and advances in synthetic DNA manufacture techniques have rapidly advanced the field of custom protein design, in which completely new proteins never before seen in nature are produced. The image shows many self-assembling protein nanocage cores (in grey), each attached to 120 copies of green fluorescent protein (GFP), providing a highly fluorescent molecule for light microscopy studies of cellular functions. The ability to design macromolecular machines in this way has tremendous potential to improve and augment the functions of natural proteins involved in all biological processes, including the production of improved drugs and vaccines that can be targeted to specific sites in the body.
A 25 nanometer icosahedral protein cage that self-assembles from protein building blocks was designed by computer and produced in Escherichia coli. The structure was checked by electron microscopy, and GFP was fused to it. Each cage consists of 20 different homo trimeric proteins, 60 in total, with each end of the protein (N and C termini) fused to GFP. The images were produced and colorized using a computer.
Jacob Bale, PhD, Yang Hsia, PhD, Lance Stewart, PhD and David Baker, PhD, HHMI and Department of Biochemistry, University of Washington, Seattle.