Manganese superoxide dismutases from Escherichia coli and from yeast mitochondria: Preliminary X-ray crystallographic studies

Abstract

The Mn superoxide dismutase from Escherichia coli has been obtained in three crystal forms: (I) from 68% saturated (NH 4) 2SO 4, space group P222 or P222 1, a = 47 A ̊ , b = 103 A ̊ , c = 47.5 A ̊ , with one subunit per asymmetric unit; (II) from 50% polyethylene glycol 6000, space group C222 1 (with approx. P4 12 12 symmetry), a = 101 A ̊ , b = 108 A ̊ , c = 180 A ̊ , with four subunits (2 molecules) per asymmetric unit; (III) from 52% polyethylene glycol with a different method of preparing the enzyme solution, space group P2 12 12, a = 47 A ̊ , b = 51 A ̊ , c = 188 A ̊ , with two subunits per asymmetric unit. The yeast mitochondrial Mn superoxide dismutase has yielded the same crystal form both from 30% 2-methyl-2,4-pentane diol and from 23% polyethylene glycol 6000: space group P2 12 12 1, a = 63 A ̊ , b = 115 A ̊ , c = 125 A ̊ , with four subunits (one molecule) per asymmetric unit. A full X-ray crystallographic study of at least one of these enzymes is planned.