Solution of a sporadic crystal form of flavodoxin
that enabled the analysis of difficult redox states. Flavodoxin is a key mediator in cellular processes, including many crucial metabolic pathways. We determined the parameters for crystal growth of a large crystal form and solved the x-ray crystal structure. Due to the large size of this particular crystal form the three-dimensional structure of other oxidation states could be determined to high resolution. This provided key evidence of a conformational change that is at the heart of the redox reaction.