Scanning electron micrograph of an in vivo grown Trypanosoma brucei cathepsin B microcrystal that grew in an Sf9 insect cell and was extracted. Cathepsin B is an enzyme that is essential to the T. brucei parasite and so is a potential target to develop a cure for African sleeping sickness. The molecular structure of the enzyme was solved from almost 200,000 individual microcrystals. This image relates to a paper that appeared in the Nov. 29, 2012, issue of Science Express, published by AAAS. The paper, by Lars Redecke at the University of Hamburg in Hamburg, Germany, and colleagues was titled, "Natively Inhibited Trypanosoma brucei Cathepsin B Structure Determined Using an X-ray Laser."