SAXSdb — 4isl

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

Kunitz-type protease inhibitor 1

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	Suppressor of tumorigenicity 14 protein × 1 （Q9Y5Y6） TETRAETHYLENE GLYCOL × 1 GLYCEROL × 3 TRIETHYLENE GLYCOL × 1 GLUTATHIONE × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SPIT1_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain B； PDBConstruct 1–60； UniProt 245–304

Suppressor of tumorigenicity 14 protein

Homo sapiens

UniProt Q9Y5Y6

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Kunitz-type protease inhibitor 1 × 1 （O43278） TETRAETHYLENE GLYCOL × 1 GLYCEROL × 3 TRIETHYLENE GLYCOL × 1 GLUTATHIONE × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	ST14_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain A； PDBConstruct 1–241； UniProt 615–855

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	4isl
Deposition date deposition_date	2013-01-16
Structure title title	Crystal Structure of the inactive Matriptase in complex with its inhibitor HAI-1
Keywords keywords	Beta barrel, Serine protease inhibitor, epithelium, 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.

4isl__assembly_1__model_1

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

Download this curve (.dat)

4isl__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4isl__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	20.00 Å
Rg (electron density)	19.07 Å
Total Rg	20.06 Å
Atom count	2408
Residues	301
Excluded volume	42446 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4isl__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 (7)

Entity 1 Entity 1 polymer

Description description	Kunitz-type protease inhibitor 1
Molecular weight formula_weight	6941.8 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B
Atom count atom_count	2622

QTEDYCLASNKVGRCRGSFPRWYYDPTEQICKSFVYGGCLGNKNNYLREEECILACRGVQ

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Drosophila melanogaster

Entity 2 Entity 2 polymer

Description description	Suppressor of tumorigenicity 14 protein
Molecular weight formula_weight	26461.8 kDa
EC 编号 ec_number	3.4.21.109
Mutation mutation	N164Q, S805A
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A

VVGGTDADEGEWPWQVSLHALGQGHICGASLISPNWLVSAAHCYIDDRGFRYSDPTQWTAFLGLHDQSQRSAPGVQERRLKRIISHPFFNDFTFDYDIALLELEKPAEYSSMVRPICLPDASHVFPAGKAIWVTGWGHTQYGGTGALILQKGEIRVIQQTTCENLLPQQITPRMMCVGFLSGGVDSCQGDAGGPLSSVEADGRIFQAGVVSWGDGCAQRNKPGVYTRLPLFRDWIKENTGV

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Komagataella pastoris

Entity 3 Entity 3 non-polymer

Description description	TETRAETHYLENE GLYCOL
Molecular weight formula_weight	194.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 4 Entity 4 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 5 Entity 5 non-polymer

Description description	TRIETHYLENE GLYCOL
Molecular weight formula_weight	150.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 6 Entity 6 non-polymer

Description description	GLUTATHIONE
Molecular weight formula_weight	307.3 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 7 Entity 7 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	172

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6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d4isla_
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

Domain ID domain_id	d4islb_
Class class	g — Small proteins
Fold Fold fold	g.8 — BPTI-like
Superfamily Superfamily superfamily	g.8.1 — BPTI-like
Family Family family	g.8.1.0 — automated matches

CATH v4.4 (3 domains)

Domain ID domain_id	4islA01
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	4islA02
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	4islB00
Class class	4 — Few Secondary Structures
Architecture architecture	10 — Irregular
Topology topology	410 — Factor Xa Inhibitor
Homologous superfamily homologous superfamily	10 — Pancreatic trypsin inhibitor Kunitz domain

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Unit-cell length a length_a	61.934 Å
Unit-cell length b length_b	61.934 Å
Unit-cell length c length_c	178.997 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	8

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

Resolution resolution	2.290 Å
Low-resolution limit resolution_low	50.000 Å
R factor r_factor	0.1861
R_work r_work	0.1838
R_free r_free	0.2318

Crystal Structure of the inactive Matriptase in complex with its inhibitor HAI-1

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

Kunitz-type protease inhibitor 1

State in the Current Structure

Other States of the Same Protein in the Database

Suppressor of tumorigenicity 14 protein

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

4isl__assembly_1__model_1

4isl__assembly_1__model_1 | I(q)

4isl__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 (7)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

CATH v4.4 (3 domains)

7. Citations (1)

Crystal Structure of the inactive Matriptase in complex with its inhibitor HAI-1

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

Kunitz-type protease inhibitor 1

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Suppressor of tumorigenicity 14 protein

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

4isl__assembly_1__model_1

4isl__assembly_1__model_1 | I(q)

4isl__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 (7)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

CATH v4.4 (3 domains)

7. Citations (1)