SAXSdb — 4b0f

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1. Protein Identity and Related Structures Protein Identity & Related Structures

C4B-BINDING PROTEIN ALPHA CHAIN

HOMO SAPIENS

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 7	CHLORIDE ION × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	C4BPA_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 8–65； UniProt 540–597 Author chain B； PDBConstruct 8–65； UniProt 540–597 Author chain C； PDBConstruct 8–65； UniProt 540–597 Author chain D； PDBConstruct 8–65； UniProt 540–597 Author chain E； PDBConstruct 8–65； UniProt 540–597 Author chain F； PDBConstruct 8–65； UniProt 540–597 Author chain G； PDBConstruct 8–65； UniProt 540–597

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

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2. Structure Basics 2. Structure Basics

Entry ID entry_id	4b0f
Deposition date deposition_date	2012-07-02
Structure title title	Heptameric core complex structure of C4b-binding (C4BP) protein from human
Keywords keywords	COMPLEMENT SYSTEM, IMMUNE SYSTEM; IMMUNE SYSTEM
Experimental Method method	X-RAY DIFFRACTION

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3. Official assembly/model SAXS Official SAXS Profiles

This page reads only the latest assembly calculations. Every curve maps to an explicit PDB entry, official biological assembly and coordinate model.

4b0f__assembly_1__model_1

Assembly 1 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

4b0f__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4b0f__assembly_1__model_1 | P(r) · Pending

P(r) will be calculated and displayed separately for the same assembly/model.

Rg（Guinier）	23.85 Å
Rg (electron density)	22.58 Å
Total Rg	23.32 Å
Atom count	2937
Residues	366
Excluded volume	52658 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4b0f__assembly_1__model_1`	heptameric （7）	Success	4.1.3-1-20251215 (887e7ef)	View Download

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4. Crystallography and Experiment 4. Crystallography & Experiment

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5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Description description	C4B-BINDING PROTEIN ALPHA CHAIN
Molecular weight formula_weight	7387.0 kDa
Source method src_method	man
Copy count entity_count	7

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D,E,F,G
Atom count atom_count	2941

SAGAHAGWETPEGCEQVLTGKRLMQCLPNPEDVKMALEVYKLSLEIEQLELQRDSARQSTLDKEL

Source Source

Source organism organism	HOMO SAPIENS
Common name common_name	HUMAN
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	ESCHERICHIA COLI

Entity 2 Entity 2 non-polymer

Description description	CHLORIDE ION
Molecular weight formula_weight	35.5 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	4

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6. Fold Classification (SCOP + CATH) 7 domains

CATH v4.4 (7 domains)

Domain ID domain_id	4b0fA00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fB00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fC00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fD00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fE00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fF00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

Domain ID domain_id	4b0fG00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	5 — Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homologous superfamily homologous superfamily	3730 —

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Unit-cell length a length_a	73.850 Å
Unit-cell length b length_b	73.850 Å
Unit-cell length c length_c	204.290 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	56

Space group space_group	P 43 21 2
Space-group number int_tables_number	96
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	46.496 Å
R factor r_factor	0.2138
R_work r_work	0.2121
R_free r_free	0.2477

Heptameric core complex structure of C4b-binding (C4BP) protein from human

1. Protein Identity and Related Structures Protein Identity & Related Structures

C4B-BINDING PROTEIN ALPHA CHAIN

State in the Current Structure

Other States of the Same Protein in the Database

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

4b0f__assembly_1__model_1

4b0f__assembly_1__model_1 | I(q)

4b0f__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 7 domains

CATH v4.4 (7 domains)

7. Citations (1)

Heptameric core complex structure of C4b-binding (C4BP) protein from human

1. Protein Identity and Related Structures Protein Identity & Related Structures

C4B-BINDING PROTEIN ALPHA CHAIN

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

4b0f__assembly_1__model_1

4b0f__assembly_1__model_1 | I(q)

4b0f__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 7 domains

CATH v4.4 (7 domains)

7. Citations (1)