SAXSdb — 3fb2

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

Spectrin alpha chain, brain spectrin

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein monomer	Monomer	Protein 1	water × 1	Consistent with protein count
2	Protein monomer	Monomer	Protein 1	water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SPTA2_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 11–218； UniProt 1337–1544 Author chain B； PDBConstruct 11–218； UniProt 1337–1544

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	3fb2
Deposition date deposition_date	2008-11-18
Structure title title	Crystal structure of the human brain alpha spectrin repeats 15 and 16. Northeast Structural Genomics Consortium target HR5563a.
Keywords keywords	;Spectrin alpha chain, brain spectrin, non-erythroid alpha chain Alpha-II spectrin, fordrin alpha chain, SPTAN1, SPTA2_HUMAN, NESG, HR5563A, Structural Genomics, PSI-2, Protein Structure Initiative, Northeast Structural Genomics Consortium, Actin capping, Actin-binding, Alternative splicing, Calcium, Calmodulin-binding, Cytoplasm, Cytoskeleton, Phosphoprotein, Polymorphism, SH3 domain, STRUCTURAL PROTEIN ;; STRUCTURAL 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.

3fb2__assembly_1__model_1

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

Download this curve (.dat)

3fb2__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3fb2__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	26.59 Å
Rg (electron density)	27.21 Å
Total Rg	27.15 Å
Atom count	1533
Residues	183
Excluded volume	26837 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3fb2__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3fb2__assembly_2__model_1`	monomeric （1）	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 (2)

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6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

Domain ID domain_id	3fb2A01
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	58 — Methane Monooxygenase Hydroxylase; Chain G, domain 1
Homologous superfamily homologous superfamily	60 —

Domain ID domain_id	3fb2A02
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	58 — Methane Monooxygenase Hydroxylase; Chain G, domain 1
Homologous superfamily homologous superfamily	60 —

Domain ID domain_id	3fb2B01
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	58 — Methane Monooxygenase Hydroxylase; Chain G, domain 1
Homologous superfamily homologous superfamily	60 —

Domain ID domain_id	3fb2B02
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	58 — Methane Monooxygenase Hydroxylase; Chain G, domain 1
Homologous superfamily homologous superfamily	60 —

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Unit-cell length a length_a	65.610 Å
Unit-cell length b length_b	96.376 Å
Unit-cell length c length_c	111.145 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	8

Space group space_group	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	2.300 Å
Low-resolution limit resolution_low	36.410 Å
R factor r_factor	0.2190
R_work r_work	0.2190
R_free r_free	0.2480

Description description	Spectrin alpha chain, brain spectrin
Molecular weight formula_weight	25665.8 kDa
Source method src_method	man
Copy count entity_count	2

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	3459

Crystal structure of the human brain alpha spectrin repeats 15 and 16. Northeast Structural Genomics Consortium target HR5563a.

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

Spectrin alpha chain, brain spectrin

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

3fb2__assembly_1__model_1

3fb2__assembly_1__model_1 | I(q)

3fb2__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

7. Citations (1)

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Escherichia coli

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	280

Crystal structure of the human brain alpha spectrin repeats 15 and 16. Northeast Structural Genomics Consortium target HR5563a.

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

Spectrin alpha chain, brain spectrin

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

3fb2__assembly_1__model_1

3fb2__assembly_1__model_1 | I(q)

3fb2__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

7. Citations (1)