SAXSdb — 2qcb

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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	;N-(4-{[(2-AMINOETHYL)AMINO]SULFONYL}PHENYL)-5-[(3AS,4S,6AR)-2-OXOHEXAHYDRO-1H-THIENO[3,4-D]IMIDAZOL-4-YL]PENTANAMIDE-(1,2,3,4,5,6-ETA)-BENZENE-CHLORO-RUTHENIUM(III) ; × 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 14–159； UniProt 38–183

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	2qcb
Deposition date deposition_date	2007-06-19
Structure title title	T7-tagged full-length streptavidin complexed with ruthenium ligand
Keywords keywords	streptavidin, t7-tag, artificial transfer hydrogenase, 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.

2qcb__assembly_1__model_1

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

Download this curve (.dat)

2qcb__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2qcb__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	22.40 Å
Rg (electron density)	21.35 Å
Total Rg	22.18 Å
Atom count	3812
Residues	488
Excluded volume	66599 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2qcb__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	16612.1 kDa
Mutation mutation	S112K
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	1089

MASMTGGQQMGRDEAGITGTWYNQLGSTFIVTAGADGALTGTYESAVGNAESRYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSATTWSGQYVGGAEARINTQWLLTKGTTEANAWKSTLVGHDTFTKVKPSAASIDAAKKAGVNNGNPLDAVQQ

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	;N-(4-{[(2-AMINOETHYL)AMINO]SULFONYL}PHENYL)-5-[(3AS,4S,6AR)-2-OXOHEXAHYDRO-1H-THIENO[3,4-D]IMIDAZOL-4-YL]PENTANAMIDE-(1,2,3,4,5,6-ETA)-BENZENE-CHLORO-RUTHENIUM(III) ;
Molecular weight formula_weight	654.2 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	112

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d2qcba2
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	d2qcba3
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	2qcbA00
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	57.651 Å
Unit-cell length b length_b	57.651 Å
Unit-cell length c length_c	183.823 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	1.650 Å
Low-resolution limit resolution_low	19.900 Å
R factor r_factor	0.1690
R_work r_work	0.1680
R_free r_free	0.1870

T7-tagged full-length streptavidin complexed with ruthenium ligand

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

2qcb__assembly_1__model_1

2qcb__assembly_1__model_1 | I(q)

2qcb__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)

T7-tagged full-length streptavidin complexed with ruthenium ligand

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

2qcb__assembly_1__model_1

2qcb__assembly_1__model_1 | I(q)

2qcb__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)