SAXSdb — 3rds

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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 monomer	Monomer	Protein 1	PENTAETHYLENE GLYCOL × 1 water × 1	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 4	PENTAETHYLENE GLYCOL × 4 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 26–153； UniProt 37–164

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	3rds
Deposition date deposition_date	2011-04-01
Structure title title	Crystal structure of the refolded R7-2 streptavidin
Keywords keywords	Streptavidin variants, improved desthiobiotin binding, opened loop destabilization, 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.

3rds__assembly_1__model_1

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

Download this curve (.dat)

3rds__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3rds__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	16.01 Å
Rg (electron density)	14.91 Å
Total Rg	15.95 Å
Atom count	914
Residues	123
Excluded volume	15943 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3rds__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3rds__assembly_2__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	15966.4 kDa
Mutation mutation	T90S, W108V, L110T, F29L, S52G, R53S
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	1091

MSGSHHHHHHSSGIEGRGRLIKHMTAEAGITGTWYNQLGSTLIVTAGADGALTGTYESAVGNAEGSYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSASTWSGQYVGGAEARINTQVLTTSGTTEANAWKSTLVGHDTFTKVKPSAASI

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	PENTAETHYLENE GLYCOL
Molecular weight formula_weight	238.3 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	127

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3rdsa1
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	d3rdsa2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

CATH v4.4 (1 domains)

Domain ID domain_id	3rdsA00
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	57.469 Å
Unit-cell length b length_b	57.469 Å
Unit-cell length c length_c	173.492 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	16

Space group space_group	I 41 2 2
Space-group number int_tables_number	98
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	19.130 Å
R factor r_factor	0.1908
R_work r_work	0.1896
R_free r_free	0.2142

Crystal structure of the refolded R7-2 streptavidin

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

3rds__assembly_1__model_1

3rds__assembly_1__model_1 | I(q)

3rds__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) 3 domains

SCOP 2.08 (2 domains)

CATH v4.4 (1 domains)

7. Citations (1)

Crystal structure of the refolded R7-2 streptavidin

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

3rds__assembly_1__model_1

3rds__assembly_1__model_1 | I(q)

3rds__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) 3 domains

SCOP 2.08 (2 domains)

CATH v4.4 (1 domains)

7. Citations (1)