SAXSdb — 1sts

▼

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 heterocomplex	Heteromer	Protein 8	FCHPQNT-NH2 × 4 water × 8	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 1–123； UniProt 37–159 Author chain D； PDBConstruct 1–123； UniProt 37–159

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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id	1sts
Deposition date deposition_date	1995-09-12
Structure title title	STREPTAVIDIN DIMERIZED BY DISULFIDE-BONDED PEPTIDE FCHPQNT-NH2 DIMER
Keywords keywords	COMPLEX (GLYCOPROTEIN-PEPTIDE), COMPLEX (GLYCOPROTEIN-PEPTIDE) complex; COMPLEX (GLYCOPROTEIN/PEPTIDE)
Experimental Method method	X-RAY DIFFRACTION

▼

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.

1sts__assembly_1__model_1

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

Download this curve (.dat)

1sts__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1sts__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	23.37 Å
Rg (electron density)	22.38 Å
Total Rg	23.35 Å
Atom count	4692
Residues	514
Excluded volume	65313 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1sts__assembly_1__model_1`	octameric （8）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Description description	STREPTAVIDIN
Molecular weight formula_weight	12965.0 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,D
Atom count atom_count	2904

AEAGITGTWYNQLGSTFIVTAGADGALTGTYESAVGNAESRYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSATTWSGQYVGGAEARINTQWLLTSGTTEANAWKSTLVGHDTFTKVKP

Entity 2 Entity 2 polymer

Description description	FCHPQNT-NH2
Molecular weight formula_weight	844.9 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	M,P

FCHPQNTX

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	158

▼

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1stsb_
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	d1stsd_
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	1stsB00
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	1stsD00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	128 — Lipocalin
Homologous superfamily homologous superfamily	30 — Avidin-like

▶

Unit-cell length a length_a	97.840 Å
Unit-cell length b length_b	105.790 Å
Unit-cell length c length_c	49.080 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	1.950 Å
Low-resolution limit resolution_low	7.500 Å
R factor r_factor	0.1910
R_work r_work	0.1910
R_free r_free	0.2380

STREPTAVIDIN DIMERIZED BY DISULFIDE-BONDED PEPTIDE FCHPQNT-NH2 DIMER

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

1sts__assembly_1__model_1

1sts__assembly_1__model_1 | I(q)

1sts__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 polymer

Polymer 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)

STREPTAVIDIN DIMERIZED BY DISULFIDE-BONDED PEPTIDE FCHPQNT-NH2 DIMER

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

1sts__assembly_1__model_1

1sts__assembly_1__model_1 | I(q)

1sts__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 polymer

Polymer 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)