SAXSdb — 1swd

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

STREPTAVIDIN

Streptomyces avidinii

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	BIOTIN × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SAV_STRAV
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–127； UniProt 37–163 Author chain B； PDBConstruct 1–127； UniProt 37–163 Author chain C； PDBConstruct 1–127； UniProt 37–163 Author chain D； PDBConstruct 1–127； UniProt 37–163

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	1swd
Deposition date deposition_date	1997-03-04
Structure title title	APO-CORE-STREPTAVIDIN IN COMPLEX WITH BIOTIN (TWO UNOCCUPIED BINDING SITES) AT PH 4.5
Keywords keywords	BIOTIN BINDING PROTEIN, BIOTIN, BIOTIN-BINDING PROTEIN; BIOTIN-BINDING PROTEIN
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.

1swd__assembly_1__model_1

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

Download this curve (.dat)

1swd__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1swd__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	22.31 Å
Rg (electron density)	21.24 Å
Total Rg	22.15 Å
Atom count	3515
Residues	464
Excluded volume	61125 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1swd__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 (3)

Entity 1 Entity 1 polymer

Description description	STREPTAVIDIN
Molecular weight formula_weight	13281.3 kDa
Source method src_method	man
Copy count entity_count	4

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D
Atom count atom_count	3749

AEAGITGTWYNQLGSTFIVTAGADGALTGTYESAVGNAESRYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSATTWSGQYVGGAEARINTQWLLTSGTTEANAWKSTLVGHDTFTKVKPSAAS

Source Source

Source organism organism	Streptomyces avidinii
NCBI taxonomy ID ncbi_taxonomy_id	1895
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	BIOTIN
Molecular weight formula_weight	244.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	234

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1swda_
Class class	b — All beta proteins
Fold Fold fold	b.61 — Streptavidin-like
Superfamily Superfamily superfamily	b.61.1 — Avidin/streptavidin
Family Family family	b.61.1.1 — Avidin/streptavidin

Domain ID domain_id	d1swdb_
Class class	b — All beta proteins
Fold Fold fold	b.61 — Streptavidin-like
Superfamily Superfamily superfamily	b.61.1 — Avidin/streptavidin
Family Family family	b.61.1.1 — Avidin/streptavidin

Domain ID domain_id	d1swdc_
Class class	b — All beta proteins
Fold Fold fold	b.61 — Streptavidin-like
Superfamily Superfamily superfamily	b.61.1 — Avidin/streptavidin
Family Family family	b.61.1.1 — Avidin/streptavidin

Domain ID domain_id	d1swdd_
Class class	b — All beta proteins
Fold Fold fold	b.61 — Streptavidin-like
Superfamily Superfamily superfamily	b.61.1 — Avidin/streptavidin
Family Family family	b.61.1.1 — Avidin/streptavidin

CATH v4.4 (4 domains)

Domain ID domain_id	1swdA00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	30 — Avidin-like

Domain ID domain_id	1swdB00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	30 — Avidin-like

Domain ID domain_id	1swdC00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	30 — Avidin-like

Domain ID domain_id	1swdD00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	30 — Avidin-like

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Unit-cell length a length_a	57.794 Å
Unit-cell length b length_b	85.191 Å
Unit-cell length c length_c	46.599 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	100.13 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	8

Space group space_group	P 1 21 1
Space-group number int_tables_number	4
Crystal system crystal_system	—

Resolution resolution	1.900 Å
Low-resolution limit resolution_low	10.000 Å
R factor r_factor	0.2020
R_work r_work	—
R_free r_free	0.3280

APO-CORE-STREPTAVIDIN IN COMPLEX WITH BIOTIN (TWO UNOCCUPIED BINDING SITES) AT PH 4.5

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

STREPTAVIDIN

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

1swd__assembly_1__model_1

1swd__assembly_1__model_1 | I(q)

1swd__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

APO-CORE-STREPTAVIDIN IN COMPLEX WITH BIOTIN (TWO UNOCCUPIED BINDING SITES) AT PH 4.5

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

STREPTAVIDIN

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

1swd__assembly_1__model_1

1swd__assembly_1__model_1 | I(q)

1swd__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)