SAXSdb — 3lbx

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

Spectrin alpha chain, erythrocyte

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Spectrin beta chain, erythrocyte × 1 （P11277）	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SPTA1_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 4–161； UniProt 1–158

Spectrin beta chain, erythrocyte

Homo sapiens

UniProt P11277

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Spectrin alpha chain, erythrocyte × 1 （P02549）	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SPTB1_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 3–185； UniProt 1902–2084

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	3lbx
Deposition date deposition_date	2010-01-08
Structure title title	Crystal Structure of the Erythrocyte Spectrin Tetramerization Domain Complex
Keywords keywords	;spectrin, tetramer, complex, three-helix bundle, alpha helix, partial repeat, helical linker, Actin capping, Actin-binding, Cell shape, Cytoskeleton, Disease mutation, Elliptocytosis, Hereditary hemolytic anemia, Pyropoikilocytosis, SH3 domain, Phosphoprotein, 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.

3lbx__assembly_1__model_1

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

Download this curve (.dat)

3lbx__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3lbx__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	42.71 Å
Rg (electron density)	44.37 Å
Total Rg	43.97 Å
Atom count	2673
Residues	322
Excluded volume	47125 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3lbx__assembly_1__model_1`	dimeric （2）	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)

Entity 1 Entity 1 polymer

Description description	Spectrin alpha chain, erythrocyte
Molecular weight formula_weight	18945.3 kDa
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	2673

GSGMEQFPKETVVESSGPKVLETAEEIQERRQEVLTRYQSFKERVAERGQKLEDSYHLQVFKRDADDLGKWIMEKVNILTDKSYEDPTNIQGKYQKHQSLEAEVQTKSRLMSELEKTREERFTMGHSAHEETKAHIEELRHLWDLLLELTLEKGDQLLRAL

Source Source

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

Entity 2 Entity 2 polymer

Description description	Spectrin beta chain, erythrocyte
Molecular weight formula_weight	21770.7 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

GSTADKFRFFSMARDLLSWMESIIRQIETQERPRDVSSVELLMKYHQGINAEIETRSKNFSACLELGESLLQRQHQASEEIREKLQQVMSRRKEMNEKWEARWERLRMLLEVCQFSRDASVAEAWLIAQEPYLASGDFGHTVDSVEKLIKRHEAFEKSTASWAERFAALEKPTTLELKERQIAER

Source Source

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

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6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

Domain ID domain_id	3lbxA00
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	3lbxB01
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	3lbxB02
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	213.901 Å
Unit-cell length b length_b	213.901 Å
Unit-cell length c length_c	31.461 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	I 41
Space-group number int_tables_number	80
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	35.000 Å
R factor r_factor	0.2694
R_work r_work	0.2680
R_free r_free	0.2994

Crystal Structure of the Erythrocyte Spectrin Tetramerization Domain Complex

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

Spectrin alpha chain, erythrocyte

State in the Current Structure

Other States of the Same Protein in the Database

Spectrin beta chain, erythrocyte

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

3lbx__assembly_1__model_1

3lbx__assembly_1__model_1 | I(q)

3lbx__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 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)

Crystal Structure of the Erythrocyte Spectrin Tetramerization Domain Complex

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

Spectrin alpha chain, erythrocyte

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Spectrin beta chain, erythrocyte

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

3lbx__assembly_1__model_1

3lbx__assembly_1__model_1 | I(q)

3lbx__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 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)