SAXSdb — 1nzi

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

Complement C1s component

Homo sapiens

State in the Current Structure

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

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	C1S_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–159； UniProt 16–174 Author chain B； PDBConstruct 1–159； UniProt 16–174

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	1nzi
Deposition date deposition_date	2003-02-18
Structure title title	Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s
Keywords keywords	CALCIUM, COMPLEMENT, INNATE IMMUNITY, MODULAR STRUCTURE, CUB, EGF, hydrolase; HYDROLASE
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.

1nzi__assembly_1__model_1

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

Download this curve (.dat)

1nzi__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1nzi__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	26.70 Å
Rg (electron density)	26.09 Å
Total Rg	26.57 Å
Atom count	2502
Residues	311
Excluded volume	43851 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1nzi__assembly_1__model_1`	dimeric （2）	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 (4)

Entity 1 Entity 1 polymer

Description description	Complement C1s component
Molecular weight formula_weight	18144.9 kDa
EC 编号 ec_number	3.4.21.42
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	2809

EPTMYGEILSPNYPQAYPSEVEKSWDIEVPEGYGIHLYFTHLDIELSENCAYDSVQIISGDTEEGRLCGQRSSNNPHSPIVEEFQVPYNKLQVIFKSDFSNEERFTGFAAYYVATDINECTDFVDVPCSHFCNNFIGGYFCSCPPEYFLHDDMKNCGVN

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Trichoplusia ni

Entity 2 Entity 2 non-polymer

Description description	CALCIUM ION
Molecular weight formula_weight	40.1 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	288

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1nzia1
Class class	b — All beta proteins
Fold Fold fold	b.23 — CUB-like
Superfamily Superfamily superfamily	b.23.1 — Spermadhesin, CUB domain
Family Family family	b.23.1.1 — Spermadhesin, CUB domain

Domain ID domain_id	d1nzia2
Class class	g — Small proteins
Fold Fold fold	g.3 — Knottins (small inhibitors, toxins, lectins)
Superfamily Superfamily superfamily	g.3.11 — EGF/Laminin
Family Family family	g.3.11.1 — EGF-type module

Domain ID domain_id	d1nzib1
Class class	b — All beta proteins
Fold Fold fold	b.23 — CUB-like
Superfamily Superfamily superfamily	b.23.1 — Spermadhesin, CUB domain
Family Family family	b.23.1.1 — Spermadhesin, CUB domain

Domain ID domain_id	d1nzib2
Class class	g — Small proteins
Fold Fold fold	g.3 — Knottins (small inhibitors, toxins, lectins)
Superfamily Superfamily superfamily	g.3.11 — EGF/Laminin
Family Family family	g.3.11.1 — EGF-type module

CATH v4.4 (4 domains)

Domain ID domain_id	1nziA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	120 — Jelly Rolls
Homologous superfamily homologous superfamily	290 — Spermadhesin, CUB domain

Domain ID domain_id	1nziA02
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	25 — Laminin
Homologous superfamily homologous superfamily	10 — Laminin

Domain ID domain_id	1nziB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	120 — Jelly Rolls
Homologous superfamily homologous superfamily	290 — Spermadhesin, CUB domain

Domain ID domain_id	1nziB02
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	25 — Laminin
Homologous superfamily homologous superfamily	10 — Laminin

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Unit-cell length a length_a	35.134 Å
Unit-cell length b length_b	47.499 Å
Unit-cell length c length_c	56.679 Å
Unit-cell angle α angle_alpha	87.74 °
Unit-cell angle β angle_beta	78.04 °
Unit-cell angle γ angle_gamma	75.67 °
Molecules per unit cell Z z_pdb	2

Space group space_group	P 1
Space-group number int_tables_number	1
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	30.000 Å
R factor r_factor	0.2173
R_work r_work	0.2160
R_free r_free	0.2340

Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s

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

Complement C1s component

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

1nzi__assembly_1__model_1

1nzi__assembly_1__model_1 | I(q)

1nzi__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s

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

Complement C1s component

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

1nzi__assembly_1__model_1

1nzi__assembly_1__model_1 | I(q)

1nzi__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)