image: This image of a knotted protein comes from a microorganism called methanobacterium thermoautotrophicum that breaks down waste products and produces methane gas. This was the first structure of the most ancient type of single-celled organism – archaebacterium. Protein-folding theory previously held that forming a knot was beyond the ability of a protein; as technology improves, biologists are determining higher-quality images of structures. Researchers used the powerful X-rays at the Advanced Photon Source at Argonne to determine the protein's structure. Argonne National Laboratory image. view more
Credit: Courtesy: Argonne National Laboratory