Neutron scattering study of the (gamma-B) catalytic domains of complement proteases activated C1r and C1s.
The catalytic domains of activated C1r and C1s, comprising the C-terminal region of the A chain (gamma), disulphide-linked to the B chain, were obtained by limited proteolysis of the native proteases with chymotrypsin and plasmin, respectively, and studied by small angle neutron scattering. For activated C1s (gamma-B), a molar mass of 45,000 +/- 5000 g/mol, and a relatively large radius of gyration (Rg) of 28 +/- 1 A were determined, excluding a single globular domain. The corresponding values for activated C1r (gamma-B)2 (90,000 g/mol, Rg = 34 +/- 1 A) are consistent with a dimer involving the loose packing of two (gamma-B) subunits. Various models of the dimer are discussed in the light of neutron scattering and other data.
Zaccaï
G
G
CNRS URA 1333, Institut Laue Langevin, Grenoble, France.
Aude
C A
CA
Thielens
N M
NM
Arlaud
G J
GJ
D002918:Chymotrypsin / Q000494:pharmacology; D015923:Complement C1r / Q000648:ultrastructure*; D003173:Complement C1s / Q000648:ultrastructure*; D004789:Enzyme Activation; D005341:Fibrinolysin / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008970:Molecular Weight; D009502:Neutrons; D011487:Protein Conformation; D012542:Scattering, Radiation; D012697:Serine Endopeptidases; D012997:Solvents
D012997:Solvents; D012697:Serine Endopeptidases; D002918:Chymotrypsin; D015923:Complement C1r; D003173:Complement C1s; D005341:Fibrinolysin