SAXSdb — 6i3z

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

Alpha-1-antitrypsin

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Fab 2H2 heavy chain × 1 Fab 2H2 light chain × 1 SODIUM ION × 2 SULFATE ION × 1 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	A1AT_HUMAN
Isoform	—
PDB entities	1, 2
Chains and sequence ranges	Author chain A； PDBConstruct 5–356； UniProt 26–377 Author chain B； PDBConstruct 1–41； UniProt 378–418

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	6i3z
Deposition date deposition_date	2018-11-08
Structure title title	Fab fragment of an antibody selective for wild-type alpha-1-antitrypsin in complex with its antigen
Keywords keywords	Antibody fragment, Antitrypsin binding, Diagnostic, Monoclonal, PROTEIN BINDING, selective, wild-type, Glu342, E342; PROTEIN BINDING
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.

6i3z__assembly_1__model_1

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

Download this curve (.dat)

6i3z__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6i3z__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	34.91 Å
Rg (electron density)	34.90 Å
Total Rg	35.16 Å
Atom count	5482
Residues	759
Excluded volume	97412 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6i3z__assembly_1__model_1`	tetrameric （4）	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	Alpha-1-antitrypsin
Molecular weight formula_weight	40018.2 kDa
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	5514

MRGSDPQGDAAQKTDTSHHDQDHPTFNKITPNLAEFAFSLYRQLAHQSNSTNIFFSPVSIATAFAMLSLGTKADTHDEILEGLNFNLTEIPEAQIHEGFQELLRTLNQPDSQLQLTTGNGLFLSEGLKLVDKFLEDVKKLYHSEAFTVNFGDTEEAKKQINDYVEKGTQGKIVDLVKELDRDTVFALVNYIFFKGKWERPFEVKDTEEEDFHVDQVTTVKVPMMKRLGMFNIQHCKKLSSWVLLMKYLGNATAIFFLPDEGKLQHLENELTHDIITKFLENEDRRSASLHLPKLSITGTYDLKSVLGQLGITKVFSNGADLSGVTEEAPLKLSKAVHKAVLTIDEKGTEAAGAMFL

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	Alpha-1-antitrypsin
Molecular weight formula_weight	4681.6 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

EAIPMSIPPEVKFNKPFVFLMIEQNTKSPLFMGKVVNPTQK

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 3 Entity 3 polymer

Description description	Fab 2H2 heavy chain
Molecular weight formula_weight	23129.9 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	H

EVQLEESGGGLVKPGGSLKLSCAASGFAFSIYDMSWVRQTPEKRLEWVAYISSGGGTTYYPDTVKGRFTISRDNAKNTLYLQMSSLKSEDTAIYYCARHAGVHYWGQGTTLTVSSAKTTPPSVYPLAPGSAAQTNSMVTLGCLVKGYFPEPVTVTWNSGSLSSGVHTFPAVLQSDLYTLSSSVTVPSSTWPSETVTCNVAHPASSTKVDKKIVPRD

Entity 4 Entity 4 polymer

Description description	Fab 2H2 light chain
Molecular weight formula_weight	23914.4 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	L

DIVMTQSPSSMYASLGERVTITCKASQDINSYLSWFQQKPGKSPKNLIYRANRLVDGVPSRFSGSGSGQDYSLTISSLEYEDMGIYYCLQYDEFPWTFGGGTKLESKRADAAPTVSIFPPSSEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYSMSSTLTLTKDEYERHNSYTCEATHKTSTSPIVKSFNRNEC

Entity 5 Entity 5 non-polymer

Description description	SODIUM ION
Molecular weight formula_weight	23.0 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 6 Entity 6 non-polymer

Description description	SULFATE ION
Molecular weight formula_weight	96.1 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	32

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6. Fold Classification (SCOP + CATH) 7 domains

SCOP 2.08 (3 domains)

Domain ID domain_id	d6i3zh_
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.1 — V set domains (antibody variable domain-like)

Domain ID domain_id	d6i3zl1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.0 — automated matches

Domain ID domain_id	d6i3zl2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

CATH v4.4 (4 domains)

Domain ID domain_id	6i3zA01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	497 — Antithrombin; Chain I, domain 2
Homologous superfamily homologous superfamily	10 — Antithrombin, subunit I, domain 2

Domain ID domain_id	6i3zA02
Class class	2 — Mainly Beta
Architecture architecture	30 — Roll
Topology topology	39 — Alpha-1-antitrypsin; domain 1
Homologous superfamily homologous superfamily	10 — Alpha-1-antitrypsin, domain 1

Domain ID domain_id	6i3zH02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6i3zL02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

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Unit-cell length a length_a	37.538 Å
Unit-cell length b length_b	51.930 Å
Unit-cell length c length_c	105.869 Å
Unit-cell angle α angle_alpha	84.31 °
Unit-cell angle β angle_beta	81.47 °
Unit-cell angle γ angle_gamma	78.95 °
Molecules per unit cell Z z_pdb	1

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

Resolution resolution	3.100 Å
Low-resolution limit resolution_low	37.820 Å
R factor r_factor	0.2632
R_work r_work	0.2608
R_free r_free	0.3073

Fab fragment of an antibody selective for wild-type alpha-1-antitrypsin in complex with its antigen

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

Alpha-1-antitrypsin

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

6i3z__assembly_1__model_1

6i3z__assembly_1__model_1 | I(q)

6i3z__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 polymer

Polymer Polymer

Entity 4 Entity 4 polymer

Polymer Polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 7 domains

SCOP 2.08 (3 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Fab fragment of an antibody selective for wild-type alpha-1-antitrypsin in complex with its antigen

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

Alpha-1-antitrypsin

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

6i3z__assembly_1__model_1

6i3z__assembly_1__model_1 | I(q)

6i3z__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 polymer

Polymer Polymer

Entity 4 Entity 4 polymer

Polymer Polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 7 domains

SCOP 2.08 (3 domains)

CATH v4.4 (4 domains)

7. Citations (1)