Crystallization and preliminary X-ray study of iso-2 azurin from the methylotrophic bacterium, Methylomonas J

The obligate methylotroph Methylomonas J possesses two distinct azurins. The iso-2 azurin, which functions as an electron acceptor for methylamine dehydrogenase, has been crystallized using two kinds of precipitants: PEG 4000 and ammonium sulfate. The crystals precipitated with PEG belong to the monoclinic system, space group P2₁, with unit-cell parameters a = 32.96, b = 33.67, c = 47.34 Å and β = 101.35°. The crystals precipitated with ammonium sulfate belong to the orthorhombic system, space group C222₁, with unit-cell parameters a = 31.52, b = 62.49 and c = 135.41 Å. The crystals diffract to 1.6 and 1.9 Å resolution, respectively, and were suitable for X-ray crystallographic studies. A Patterson search is being conducted using the recently reported structure of Alcaligenes xylosoxidans NCIMB 11015 as a starting model.