The combination of NMR, cryo-electron microscopy and modeling enabled the scientists to determine that the chlorophyll molecules in green sulfur bacteria are arranged in helices. In the mutant bacteria, the chlorophyll molecules are positioned at a nearly 90-degree angle in relation to the long axis of the nanotubes, whereas the angle is less steep in the wild-type organism. The structural framework can accommodate disorder to improve the biological light harvesting function, which implies that a less ordered structure has a better performance.