SAXSdb — 1slf

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

STREPTAVIDIN

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	SULFATE ION × 8 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 B； PDBConstruct 1–135； UniProt 25–159 Author chain D； PDBConstruct 1–135； UniProt 25–159

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	1slf
Deposition date deposition_date	1995-03-10
Structure title title	APOSTREPTAVIDIN, PH 5.6, TWO MOLECULES OF (SO4)2 BOUND AT THE BIOTIN BINDING SITE
Keywords keywords	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.

1slf__assembly_1__model_1

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

Download this curve (.dat)

1slf__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1slf__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	22.72 Å
Rg (electron density)	21.79 Å
Total Rg	22.68 Å
Atom count	4534
Residues	488
Excluded volume	63707 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1slf__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)

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1slfb_
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	d1slfd_
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 (2 domains)

Domain ID domain_id	1slfB00
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	1slfD00
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	95.430 Å
Unit-cell length b length_b	106.120 Å
Unit-cell length c length_c	47.540 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 2 2 2
Space-group number int_tables_number	23
Crystal system crystal_system	—

Resolution resolution	1.760 Å
Low-resolution limit resolution_low	7.500 Å
R factor r_factor	0.1760
R_work r_work	0.1760
R_free r_free	0.2020

Description description	STREPTAVIDIN
Molecular weight formula_weight	14181.3 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,D
Atom count atom_count	2854

APOSTREPTAVIDIN, PH 5.6, TWO MOLECULES OF (SO4)2 BOUND AT THE BIOTIN BINDING SITE

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

1slf__assembly_1__model_1

1slf__assembly_1__model_1 | I(q)

1slf__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	4

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	180

APOSTREPTAVIDIN, PH 5.6, TWO MOLECULES OF (SO4)2 BOUND AT THE BIOTIN BINDING SITE

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

1slf__assembly_1__model_1

1slf__assembly_1__model_1 | I(q)

1slf__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)