Structure of methemerythrin at 5 Å resolution

Methemerythrin from Themiste dyscritum crystallizes in the tetragonal system with a=b=86·58(4) Å, c=80·84(4) A,A, space group P4 and two octameric molecules of weight ≈108,000 daltons per unit cell. Since the molecules were found to lie on the 4-fold axes, the asymmetric unit is composed of two subunits from one of the molecules in the unit cell and two from the other one. The electron density map at 5 Å resolution was based on phases calculated...