Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 87.74 kDa 
• Atom Count: 6,118 
• Modelled Residue Count: 710 
• Deposited Residue Count: 752 
• Unique protein chains: 1

 2OK5

Human Complement factor B

• PDB DOI: 10.2210/pdb2OK5/pdb

• Classification: HYDROLASE
• Organism(s): Homo sapiens
• Expression System: Homo sapiens
• Mutation(s): No 


• 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: 2.30 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
• Primary Citation of Related Structures:  
  2OK5


• 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

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Complement factor B	A	752	Homo sapiens	Mutation(s): 0  Gene Names: CFB, BF, BFD EC: 3.4.21.47
UniProt & NIH Common Fund Data Resources
Find proteins for P00751 (Homo sapiens) Explore P00751  Go to UniProtKB:  P00751
PHAROS:  P00751

Oligosaccharides

Help

Entity ID: 2
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]alpha-D-mannopyranose-(1-6)-[alpha-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose	B	7		N-Glycosylation
Glycosylation Resources
GlyTouCan:  G55220VL GlyCosmos:  G55220VL GlyGen:  G55220VL

Entity ID: 3
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose	C	2		N-Glycosylation
Glycosylation Resources
GlyTouCan:  G42666HT GlyCosmos:  G42666HT GlyGen:  G42666HT

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
NAG	D [auth A], E [auth A]	2-acetamido-2-deoxy-beta-D-glucopyranose C8 H15 N O6 OVRNDRQMDRJTHS-FMDGEEDCSA-N
GOL	F [auth A], G [auth A], H [auth A], I [auth A], J [auth A], K [auth A], L [auth A], M [auth A], N [auth A], O [auth A], P [auth A], Q [auth A], R [auth A]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 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
b = 104.031	β = 90
c = 151.116	γ = 120

Software Package:

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

Structure Validation

Entry History 

Deposition Data

• 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
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Advisory, Refinement description, Version format compliance
• Version 2.0: 2020-07-29
  Type: Remediation
  Reason: Carbohydrate remediation
  Changes: Atomic model, Data collection, Database references, Derived calculations, Structure summary
• Version 2.1: 2021-03-31
  Changes: Source and taxonomy, Structure summary