NASA astronaut Nick Hague holds research samples

iss060e015014 (7/28/2019) — NASA astronaut Nick Hague is shown holding the CASIS Protein Crystal Growth 15 (CASIS PCG 15) investigation samples aboard the International Space Station (ISS). Microgravity Crystal Growth for Improvement in Neutron Diffraction and the Analysis of Protein Complexes (CASIS PCG 15) seeks a better understanding of enzyme catalysis by examining crystals from two model Pyridoxal phosphate (PLP) dependent enzymes and from a bacteriophage transient deoxyribonucleic acid (DNA) repair complex. Analysis of the crystals may reveal catalyst mechanisms and structures and visualize the interaction between the repair proteins. Results could contribute to identification of biomarkers for diagnosis of disease and to development of better antimicrobials.