SAXSdb — 1ekb

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

ENTEROPEPTIDASE

Bos taurus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	VAL-ASP-ASP-ASP-ASP-LYK PEPTIDE × 1 ZINC ION × 2 water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	ENTK_BOVIN
Isoform	—
PDB entities	1, 2
Chains and sequence ranges	Author chain A； PDBConstruct 1–13； UniProt 788–800 Author chain B； PDBConstruct 1–235； UniProt 801–1035

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	1ekb
Deposition date deposition_date	1999-05-02
Structure title title	THE SERINE PROTEASE DOMAIN OF ENTEROPEPTIDASE BOUND TO INHIBITOR VAL-ASP-ASP-ASP-ASP-LYS-CHLOROMETHANE
Keywords keywords	ENTEROPEPTIDASE, TRYPSINOGEN ACTIVATION, HYDROLASE-HYDROLASE INHIBITOR COMPLEX; HYDROLASE/HYDROLASE INHIBITOR
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.

1ekb__assembly_1__model_1

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

Download this curve (.dat)

1ekb__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1ekb__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	17.80 Å
Rg (electron density)	16.59 Å
Total Rg	17.63 Å
Atom count	1913
Residues	245
Excluded volume	33830 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1ekb__assembly_1__model_1`	trimeric （3）	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 (5)

Entity 1 Entity 1 polymer

Description description	ENTEROPEPTIDASE
Molecular weight formula_weight	1419.7 kDa
EC 编号 ec_number	3.4.21.9
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	2021

CGKKLVTQEVSPK

Source Source

Source organism organism	Bos taurus
Common name common_name	cattle
NCBI taxonomy ID ncbi_taxonomy_id	9913
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 2 Entity 2 polymer

Description description	ENTEROPEPTIDASE
Molecular weight formula_weight	26283.8 kDa
EC 编号 ec_number	3.4.21.9
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

IVGGSDSREGAWPWVVALYFDDQQVCGASLVSRDWLVSAAHCVYGRNMEPSKWKAVLGLHMASNLTSPQIETRLIDQIVINPHYNKRRKNNDIAMMHLEMKVNYTDYIQPICLPEENQVFPPGRICSIAGWGALIYQGSTADVLQEADVPLLSNEKCQQQMPEYNITENMVCAGYEAGGVDSCQGDSGGPLMCQENNRWLLAGVTSFGYQCALPNRPGVYARVPRFTEWIQSFLH

Source Source

Source organism organism	Bos taurus
Common name common_name	cattle
NCBI taxonomy ID ncbi_taxonomy_id	9913
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 3 Entity 3 polymer

Description description	VAL-ASP-ASP-ASP-ASP-LYK PEPTIDE
Molecular weight formula_weight	740.2 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

VDDDDKX

Entity 4 Entity 4 non-polymer

Description description	ZINC ION
Molecular weight formula_weight	65.4 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	108

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d1ekbb_
Class class	b — All beta proteins
Fold Fold fold	b.47 — Trypsin-like serine proteases
Superfamily Superfamily superfamily	b.47.1 — Trypsin-like serine proteases
Family Family family	b.47.1.2 — Eukaryotic proteases

CATH v4.4 (2 domains)

Domain ID domain_id	1ekbB01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	1ekbB02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

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Unit-cell length a length_a	39.990 Å
Unit-cell length b length_b	70.650 Å
Unit-cell length c length_c	85.220 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 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	2.300 Å
Low-resolution limit resolution_low	30.000 Å
R factor r_factor	—
R_work r_work	0.2340
R_free r_free	0.2690

THE SERINE PROTEASE DOMAIN OF ENTEROPEPTIDASE BOUND TO INHIBITOR VAL-ASP-ASP-ASP-ASP-LYS-CHLOROMETHANE

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

ENTEROPEPTIDASE

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

1ekb__assembly_1__model_1

1ekb__assembly_1__model_1 | I(q)

1ekb__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 (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

CATH v4.4 (2 domains)

7. Citations (1)

THE SERINE PROTEASE DOMAIN OF ENTEROPEPTIDASE BOUND TO INHIBITOR VAL-ASP-ASP-ASP-ASP-LYS-CHLOROMETHANE

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

ENTEROPEPTIDASE

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

1ekb__assembly_1__model_1

1ekb__assembly_1__model_1 | I(q)

1ekb__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 (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

CATH v4.4 (2 domains)

7. Citations (1)