CATH Classification

Domain Context

CATH Clusters

Superfamily Complement Module, domain 1
Functional Family Mannan-binding lectin serine protease 1

Enzyme Information

3.4.21.41
Complement subcomponent C1r.
based on mapping to UniProt P00736
Selective cleavage of Lys(or Arg)-|-Ile bond in complement subcomponent C1s to form the active form of C1s (EC 3.4.21.42).
-!- Activates C1s by proteolytic cleavage so that it can, in turn, activate C2 and C4. -!- Activated from proenzyme C1r in plasma by autocatalytic mechanism during activation of the complement system by the 'classical' route. -!- Belongs to peptidase family S1.

UniProtKB Entries (1)

P00736
C1R_HUMAN
Homo sapiens
Complement C1r subcomponent

PDB Structure

PDB 1MD8
External Links
Method X-RAY DIFFRACTION
Organism Trichoplusia
Primary Citation
Monomeric structures of the zymogen and active catalytic domain of complement protease c1r: further insights into the c1 activation mechanism
Budayova-Spano, M., Grabarse, W., Thielens, N.M., Hillen, H., Lacroix, M., Schmidt, M., Fontecilla-Camps, J., Arlaud, G.J., Gaboriaud, C.
Structure