Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 87865.38 
• Atom Count: 5823 
• Residue Count: 752 
• Unique protein chains: 1

2OK5

Human Complement factor B

• DOI: 10.2210/pdb2OK5/pdb

• Classification: HYDROLASE
• Organism(s): Homo sapiens
• Expression System: Homo sapiens


• Deposited: 2007-01-16 Released: 2007-02-27 
• Deposition Author(s): Milder, F.J., Gomes, L., Schouten, A., Janssen, B.J.C., Huizinga, E.G., Romijn, R.A., Hemrika, W., Roos, A., Daha, M.R., Gros, P.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.3 Å
• R-Value Free: 0.241 
• R-Value Work: 0.195 

Literature

Factor B structure provides insights into activation of the central protease of the complement system.

Milder, F.J., Gomes, L., Schouten, A., Janssen, B.J., Huizinga, E.G., Romijn, R.A., Hemrika, W., Roos, A., Daha, M.R., Gros, P.

(2007) Nat.Struct.Mol.Biol. 14: 224-228

• PubMed: 17310251 
• DOI: 10.1038/nsmb1210


• PubMed Abstract: 
  

Factor B is the central protease of the complement system of immune defense. Here, we present the crystal structure of human factor B at 2.3-A resolution, which reveals how the five-domain proenzyme is kept securely inactive. The canonical activation helix of the Von Willebrand factor A (VWA) domain is displaced by a helix from the preceding domain linker. The two helices conformationally link the scissile-activation peptide and the metal ion-dependent adhesion site required for binding of the ligand C3b. The data suggest that C3b binding displaces the three N-terminal control domains and reshuffles the two central helices. Reshuffling of the helices releases the scissile bond for final proteolytic activation and generates a new interface between the VWA domain and the serine protease domain. This allosteric mechanism is crucial for tight regulation of the complement-amplification step in the immune response.

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Organizational Affiliation: 

Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Complement factor B	A	752	Homo sapiens	Mutation(s): 0  Gene Names: CFB (BF, BFD) EC: 3.4.21.47
Find proteins for P00751 (Homo sapiens) Go to Gene View: CFB Go to UniProtKB:  P00751

Small Molecules

Ligands 4 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
GOL	A	GLYCEROL GLYCERIN; PROPANE-1,2,3-TRIOL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
MAN	A	ALPHA-D-MANNOSE C6 H12 O6 WQZGKKKJIJFFOK-PQMKYFCFSA-N
BMA	A	BETA-D-MANNOSE C6 H12 O6 WQZGKKKJIJFFOK-RWOPYEJCSA-N
NAG	A	N-ACETYL-D-GLUCOSAMINE C8 H15 N O6 OVRNDRQMDRJTHS-FMDGEEDCSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.3 Å
• R-Value Free: 0.241 
• R-Value Work: 0.195 
• Space Group: P 3₁ 2 1

Unit Cell:

Length (Å)	Angle (°)
a = 104.031	α = 90.00
b = 104.031	β = 90.00
c = 151.116	γ = 120.00

Software Package:

Software Name	Purpose
CCP4	data scaling
PHASER	phasing
DNA	data collection
REFMAC	refinement
MOSFLM	data reduction

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2007-01-16 
• Released Date: 2007-02-27 
• Deposition Author(s): Milder, F.J., Gomes, L., Schouten, A., Janssen, B.J.C., Huizinga, E.G., Romijn, R.A., Hemrika, W., Roos, A., Daha, M.R., Gros, P.

Revision History 

• Version 1.0: 2007-02-27
  Type: Initial release
• Version 1.1: 2008-05-01
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Advisory, Refinement description, Version format compliance