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The structure of complement complex

Source organism: Homo sapiens
Biochemical function: endopeptidase inhibitor activity
Biological process: proteolysis
Cellular component: membrane

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EC 3.4.21.45: Complement factor I

Reaction catalysed:
Inactivates complement subcomponents C3b, iC3b and C4b by proteolytic cleavage.
Systematic name:
-
Alternative Name(s):
  • C3b inactivator
  • C3b/C4b inactivator
  • C3bINA
  • Complement C3b inactivator
  • Complement C3b/C4b inactivator
  • Complement C4b inactivator
  • Complement C4bi
  • Complement component C3b inactivator
  • Conglutinogen-activating factor C
  • Factor I

GO terms

Biochemical function:
Biological process:
Cellular component:

Sequence families

Pfam Protein families (Pfam)
PF00084
Domain description: Sushi repeat (SCR repeat)
Occurring in:
  1. Complement factor H
The deposited structure of PDB entry 5o32 contains 12 copies of Pfam domain PF00084 (Sushi repeat (SCR repeat)) in Complement factor H. Showing 6 copies in chain C.

PF00057
Domain description: Low-density lipoprotein receptor domain class A
Occurring in:
  1. Complement factor I heavy chain
The deposited structure of PDB entry 5o32 contains 4 copies of Pfam domain PF00057 (Low-density lipoprotein receptor domain class A) in Complement factor I heavy chain. Showing 2 copies in chain D.

PF00089
Domain description: Trypsin
Occurring in:
  1. Complement factor I light chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF00089 (Trypsin) in Complement factor I light chain. Showing 1 copy in chain E [auth I].

PF00530
Domain description: Scavenger receptor cysteine-rich domain
Occurring in:
  1. Complement factor I heavy chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF00530 (Scavenger receptor cysteine-rich domain) in Complement factor I heavy chain. Showing 1 copy in chain D.

PF21287
Domain description: Complement factor I, KAZAL domain
Occurring in:
  1. Complement factor I heavy chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF21287 (Complement factor I, KAZAL domain) in Complement factor I heavy chain. Showing 1 copy in chain D.

PF21286
Domain description: Complement factor I, FIMAC N-terminal domain
Occurring in:
  1. Complement factor I heavy chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF21286 (Complement factor I, FIMAC N-terminal domain) in Complement factor I heavy chain. Showing 1 copy in chain D.

PF01759
Domain description: UNC-6/NTR/C345C module
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF01759 (UNC-6/NTR/C345C module) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF07677
Domain description: A-macroglobulin receptor binding domain
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF07677 (A-macroglobulin receptor binding domain) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF21308
Domain description: Complement component 3, CUB domain, second segment
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF21308 (Complement component 3, CUB domain, second segment) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF07678
Domain description: A-macroglobulin TED domain
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF07678 (A-macroglobulin TED domain) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF21406
Domain description: Complement component 3, CUB domain, first segment
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF21406 (Complement component 3, CUB domain, first segment) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF00207
Domain description: Alpha-2-macroglobulin family
Occurring in:
  1. Complement C3b alpha' chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF00207 (Alpha-2-macroglobulin family) in Complement C3b alpha' chain. Showing 1 copy in chain B.

PF07703
Domain description: Alpha-2-macroglobulin bait region domain
Occurring in:
  1. Complement C3 beta chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF07703 (Alpha-2-macroglobulin bait region domain) in Complement C3 beta chain. Showing 1 copy in chain A.

PF17789
Domain description: Macroglobulin domain MG4
Occurring in:
  1. Complement C3 beta chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF17789 (Macroglobulin domain MG4) in Complement C3 beta chain. Showing 1 copy in chain A.

PF17791
Domain description: Macroglobulin domain MG3
Occurring in:
  1. Complement C3 beta chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF17791 (Macroglobulin domain MG3) in Complement C3 beta chain. Showing 1 copy in chain A.

PF01835
Domain description: MG2 domain
Occurring in:
  1. Complement C3 beta chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF01835 (MG2 domain) in Complement C3 beta chain. Showing 1 copy in chain A.

PF17790
Domain description: Macroglobulin domain MG1
Occurring in:
  1. Complement C3 beta chain
The deposited structure of PDB entry 5o32 contains 2 copies of Pfam domain PF17790 (Macroglobulin domain MG1) in Complement C3 beta chain. Showing 1 copy in chain A.

InterPro InterPro annotations
IPR000436
Domain description: Sushi/SCR/CCP domain
Occurring in:
  1. Complement factor H
IPR002172
Domain description: Low-density lipoprotein (LDL) receptor class A repeat
Occurring in:
  1. Complement factor I heavy chain
IPR035976
Domain description: Sushi/SCR/CCP superfamily
Occurring in:
  1. Complement factor H
IPR036055
Domain description: LDL receptor-like superfamily
Occurring in:
  1. Complement factor I heavy chain
IPR001314
Domain description: Peptidase S1A, chymotrypsin family
Occurring in:
  1. Complement factor I light chain
IPR001254
Domain description: Serine proteases, trypsin domain
Occurring in:
  1. Complement factor I light chain
IPR001190
Domain description: SRCR domain
Occurring in:
  1. Complement factor I heavy chain
IPR036772
Domain description: SRCR-like domain superfamily
Occurring in:
  1. Complement factor I heavy chain
IPR018933
Domain description: Netrin module, non-TIMP type
Occurring in:
  1. Complement C3b alpha' chain
IPR008993
Domain description: Tissue inhibitor of metalloproteinases-like, OB-fold
Occurring in:
  1. Complement C3b alpha' chain
IPR009048
Domain description: Alpha-macroglobulin, receptor-binding
Occurring in:
  1. Complement C3b alpha' chain
IPR036595
Domain description: Alpha-macroglobulin, receptor-binding domain superfamily
Occurring in:
  1. Complement C3b alpha' chain
IPR013783
Domain description: Immunoglobulin-like fold
Occurring in:
  1. Complement C3 beta chain
  2. Complement C3b alpha' chain
IPR033116
Domain description: Serine proteases, trypsin family, serine active site
Occurring in:
  1. Complement factor I light chain
IPR018114
Domain description: Serine proteases, trypsin family, histidine active site
Occurring in:
  1. Complement factor I light chain
IPR043504
Domain description: Peptidase S1, PA clan, chymotrypsin-like fold
Occurring in:
  1. Complement factor I light chain
IPR009003
Domain description: Peptidase S1, PA clan
Occurring in:
  1. Complement factor I light chain
IPR023415
Domain description: Low-density lipoprotein (LDL) receptor class A, conserved site
Occurring in:
  1. Complement factor I heavy chain
IPR002350
Domain description: Kazal domain
Occurring in:
  1. Complement factor I heavy chain
IPR036058
Domain description: Kazal domain superfamily
Occurring in:
  1. Complement factor I heavy chain
IPR003884
Domain description: Factor I / membrane attack complex
Occurring in:
  1. Complement factor I heavy chain
IPR001134
Domain description: Netrin domain
Occurring in:
  1. Complement C3b alpha' chain
IPR035815
Domain description: Complement C3-like, NTR domain
Occurring in:
  1. Complement C3b alpha' chain
IPR019742
Domain description: Alpha-2-macroglobulin, conserved site
Occurring in:
  1. Complement C3b alpha' chain
IPR047565
Domain description: Alpha-macroglobulin-like, thiol-ester bond-forming region
Occurring in:
  1. Complement C3b alpha' chain
IPR008930
Domain description: Terpenoid cyclases/protein prenyltransferase alpha-alpha toroid
Occurring in:
  1. Complement C3b alpha' chain
IPR011626
Domain description: Alpha-macroglobulin-like, TED domain
Occurring in:
  1. Complement C3b alpha' chain
IPR001599
Domain description: Alpha-2-macroglobulin
Occurring in:
  1. Complement C3b alpha' chain
IPR011625
Domain description: Alpha-2-macroglobulin, bait region domain
Occurring in:
  1. Complement C3 beta chain
IPR040839
Domain description: Macroglobulin domain MG4
Occurring in:
  1. Complement C3 beta chain
IPR041555
Domain description: Macroglobulin domain MG3
Occurring in:
  1. Complement C3 beta chain
IPR002890
Domain description: Macroglobulin domain
Occurring in:
  1. Complement C3 beta chain
IPR041425
Domain description: Complement C3/4/5, macroglobulin domain MG1
Occurring in:
  1. Complement C3 beta chain

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