Crystallization, preliminary X-ray analysis and molecular-replacement solution of haemoglobin-II from the fish matrinxã (Brycon cephalus)

Haemoglobins constitute a set of proteins with interesting structural and functional properties, especially when the two large animal groups reptiles and fishes are focused on. Here, the crystallization and preliminary X-ray analysis of haemoglobin-II from the South American fish matrinxã (Brycon cephalus) is reported. X-ray diffraction data have been collected to 3.0 Å resolution using synchrotron radiation (LNLS). Crystals were determined to belong to space group P2₁ and preliminary structural analysis revealed the presence of two tetramers in the asymmetric unit. The structure was determined using the standard molecular-replacement technique.