Better by design: Four helices form the backbone of a man-made protein.
A synthetic protein built from scratch can carry oxygen, mimicking blood
Source: “Design and engineering of an O(2) transport protein”
P. Leslie Dutton et al.
Nature 458: 305-309
Results: Scientists at the University of Pennsylvania have designed and built a protein that can transport oxygen. The protein is much simpler than the oxygen-carrying proteins found in nature, and the process that they used demonstrates a new method for making novel proteins.
Why it matters: A more complex version of the protein could eventually be used to create artificial blood. The research also illustrates the effectiveness of the new design process, which could be used to engineer other proteins that improve on the efficiency of important biological functions–or proteins with entirely new functions.
Methods: The design process begins with a simple artificial protein that the researchers gradually change until it performs a desired function. To make the oxygen-binding protein, the researchers used three amino acids, the building blocks of proteins, to create four novel helix-shaped structures that they assembled into a bundle. Then they replaced some of these amino acids with ones that would help the bundle incorporate a chemical group called a heme, which can bind oxygen molecules. They added other amino acids to help make the protein structure flexible enough to open, letting the heme bind oxygen, and then close, protecting the oxygen from water.
Next steps: Researchers plan to engineer artificial functional proteins that incorporate light-harvesting pigments to capture solar energy.