SAXSdb — 2qos

▼

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

Complement component 8, gamma polypeptide

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Complement component C8 alpha chain × 1 （P07357） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q14CU0_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain C； PDBConstruct 1–173； UniProt 30–202

Complement component C8 alpha chain

OrganismNot specified

UniProt P07357

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Complement component 8, gamma polypeptide × 1 （Q14CU0） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CO8A_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain A； PDBConstruct 1–11； UniProt 188–198

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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id	2qos
Deposition date deposition_date	2007-07-20
Structure title title	Crystal structure of complement protein C8 in complex with a peptide containing the C8 binding site on C8
Keywords keywords	;Beta barrel, lipocalin, Cleavage on pair of basic residues, Complement alternate pathway, Complement pathway, Cytolysis, EGF-like domain, Glycoprotein, Immune response, Innate immunity, Membrane attack complex, Polymorphism, Secreted, IMMUNE SYSTEM ;; IMMUNE SYSTEM
Experimental Method method	X-RAY DIFFRACTION

▼

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.

2qos__assembly_1__model_1

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

Download this curve (.dat)

2qos__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2qos__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	16.94 Å
Rg (electron density)	15.40 Å
Total Rg	16.57 Å
Atom count	1437
Residues	184
Excluded volume	25412 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2qos__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Description description	Complement component 8, gamma polypeptide
Molecular weight formula_weight	19171.6 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C
Atom count atom_count	1601

ASPISTIQPKANFDAQQFAGTWLLVAVGSAARFLQEQGHRAEATTLHVAPQGTAMAVSTFRKLDGICWQVRQLYGDTGVLGRFLLQARGARGAVHVVVAETDYQSFAVLYLERAGQLSVKLYARSLPVSDSVLSGFEQRVQEAHLTEDQIFYFPKYGFCEAADQFHVLDEVRR

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 polymer

Description description	Complement component C8 alpha chain
Molecular weight formula_weight	1388.5 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A

LRYDSTAERLY

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	164

▼

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d2qosc_
Class class	b — All beta proteins
Fold Fold fold	b.60 — Lipocalins
Superfamily Superfamily superfamily	b.60.1 — Lipocalins
Family Family family	b.60.1.1 — Retinol binding protein-like

CATH v4.4 (1 domains)

Domain ID domain_id	2qosC00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	20 — Calycin beta-barrel core domain

▶

Unit-cell length a length_a	59.942 Å
Unit-cell length b length_b	85.251 Å
Unit-cell length c length_c	41.899 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	4

Space group space_group	P 21 21 2
Space-group number int_tables_number	18
Crystal system crystal_system	—

Resolution resolution	1.810 Å
Low-resolution limit resolution_low	37.600 Å
R factor r_factor	—
R_work r_work	0.2040
R_free r_free	0.2440

Crystal structure of complement protein C8 in complex with a peptide containing the C8 binding site on C8

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

Complement component 8, gamma polypeptide

State in the Current Structure

Other States of the Same Protein in the Database

Complement component C8 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

2qos__assembly_1__model_1

2qos__assembly_1__model_1 | I(q)

2qos__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 polymer

Polymer Polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (1)

Crystal structure of complement protein C8 in complex with a peptide containing the C8 binding site on C8

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

Complement component 8, gamma polypeptide

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Complement component C8 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

2qos__assembly_1__model_1

2qos__assembly_1__model_1 | I(q)

2qos__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 polymer

Polymer Polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (1)