CATH Classification

Domain Context

CATH Clusters

Superfamily Trypsin-like serine proteases
Functional Family Complement C1r subcomponent

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 2QY0
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Revisiting the mechanism of the autoactivation of the complement protease C1r in the C1 complex: Structure of the active catalytic region of C1r.
Kardos, J., Harmat, V., Pallo, A., Barabas, O., Szilagyi, K., Graf, L., Naray-Szabo, G., Goto, Y., Zavodszky, P., Gal, P.
Mol.Immunol.