Effect of Microgravity on the Crystallization of Cardiotoxin from the Venom of Spectacled Cobra Naja Naja

Cardiotoxins, which belong to the family of three-finger toxins, are the main components of cobra venom. They exhibit various types of biological activity, including antimicrobial and cytotoxic against cancer cells. Data on the minimal structural differences between individual toxins are necessary for understanding the molecular mechanisms of their action. This information can be obtained by high-resolution X-ray diffraction analysis. The influence of microgravity on the crystal packing and diffraction quality of crystals of cardiotoxin from cobra Naja naja has been investigated. Cardiotoxin crystals, which were grown on the International Space Station, provided maximally high resolution for the structure of this toxin. Protein crystallized extremely in the hexagonal space group, whereas more than half of crystals grown under laboratory conditions belonged to the orthorhombic system.