SANS data from solutions of sulfite reductase flavoprotein octamer reduced with 10 molar equivalents sodium dithionite in 50 mM KPi, 100 mM NaCl, 1 mM EDTA, pH 7.8 were collected using the EQ-SANS (BL-6) spallation neutron source (Oak Ridge, Tennessee, USA). This sample is an octamer of His-tagged sulfite reductase flavoprotein subunits. Two instrument configurations were used: 4 m sample-to-detector distance with 1.0 nm wavelength band, 2.5 m sample-to-detector distance with 0.25 nm wavelength band. Sample concentration: 3 mg/mL. Neutron exposure time: 1 hour / instrument configuration. Sample temperature: 8°C.