Crystallization and preliminary X-ray analysis of methylamine-treated alpha 2-macroglobulin and 3 alpha 2-macroglobulin-proteinase complexes.
Crystals of methylamine-treated alpha 2-macroglobulin (alpha 2M-MA), alpha 2-macroglobulin in complex with two molecules of trypsin, alpha 2M-T2, one molecule of plasmin, alpha 2M-PL, and one molecule of plasmin followed by methylamine-treatment, alpha 2M-PL(MA), have reproducibly been obtained using ammonium sulfate or magnesium sulfate as precipitants. The crystals are fragile tetragonal bipyramids of up to 1.5 mm in length. Crystals of alpha 2M-MA diffracted to at least 9 A resolution, crystals of alpha 2M-T2 diffracted to 10 A resolution and crystals of alpha 2M-PL and alpha 2M-PL(MA) diffracted to 11 A resolution. For alpha 2M-MA the cell parameters were determined as: a=b=257 A, c=555 A; and for alpha 2M-T2 as: a=b=247 A, c=559 A. For both preparations the space group was I4(1)22. As estimated from density measurements, the crystals of alpha 2M-MA and alpha 2M-T2 contain one 360 kDa alpha 2M dimer per asymmetric unit. The volume of the asymmetric unit/molecular weight, Vm, was estimated at 5.6 A3/Da. The crystal parameters of alpha 2M-PL and alpha 2M-PL(MA) were not determined.
Andersen
G R
GR
Department of Chemistry, University of Aarhus, Denmark.
Jacobsen
L
L
Thirup
S
S
Nyborg
J
J
Sottrup-Jensen
L
L
D003460:Crystallization; D010450:Endopeptidases / Q000737:chemistry*; D006801:Humans; D014961:X-Ray Diffraction; D000511:alpha-Macroglobulins / Q000737:chemistry*
D000511:alpha-Macroglobulins; D010450:Endopeptidases