Purification, crystallization and preliminary X-ray analysis of human mannose-binding lectin-associated serine protease-1 (MASP-1) catalytic region.
MASP-1, a multidomain serine protease, is a component of the lectin pathway of complement. Its precise function is unknown, although it seems to enhance the complement-activating capacity of MASP-2, a related enzyme. MASP-1 has also been implicated as playing a role in blood coagulation. It is mostly found associated with mannose-binding lectin (MBL) and ficolins. Early attempts to crystallize MASP-1 failed because of the inhomogeneity of the purified material. MASP-1 was shown by acidic nondenaturing PAGE to be composed of differently charged species, which are most likely to be the products of deamidation occurring during the refolding procedure. Sequential cation-exchange and anion-exchange chromatography resulted in a homogeneous material, which was successfully crystallized. The best crystal diffracted to 2.55 A resolution and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 68.4, b = 70.4, c = 121.4 A. The crystal structure of MASP-1 may help in understanding the function of this mysterious serine protease.
Dobó
József
J
Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Karolina út 29, H-1113 Budapest, Hungary. dobo@enzim.hu
Harmat
Veronika
V
Sebestyén
Edina
E
Beinrohr
László
L
Závodszky
Péter
P
Gál
Péter
P