SAXSdb — 1nu4

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

U1A RNA binding domain

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	MAGNESIUM ION × 2 MALONIC ACID × 6 water × 1	Consistent with protein count
2	Protein monomer	Monomer	Protein 1	MAGNESIUM ION × 3 MALONIC ACID × 6 water × 1	Consistent with protein count
3	Protein homooligomer	Homooligomer	Protein 6	MAGNESIUM ION × 15 MALONIC ACID × 36 water × 6	Consistent with protein count
4	Protein homooligomer	Homooligomer	Protein 3	MAGNESIUM ION × 9 MALONIC ACID × 18 water × 3	Consistent with protein count
5	Protein homooligomer	Homooligomer	Protein 3	MAGNESIUM ION × 6 MALONIC ACID × 18 water × 3	Consistent with protein count
6	Protein homooligomer	Homooligomer	Protein 2	MAGNESIUM ION × 4 MALONIC ACID × 12 water × 2	Consistent with protein count
7	Protein homooligomer	Homooligomer	Protein 2	MAGNESIUM ION × 6 MALONIC ACID × 12 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SNRPA_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–97； UniProt 2–98 Author chain B； PDBConstruct 1–97； UniProt 2–98

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	1nu4
Deposition date deposition_date	2003-01-30
Structure title title	U1A RNA binding domain at 1.8 angstrom resolution reveals a pre-organized C-terminal helix
Keywords keywords	RNA recognition motif, U1 small nuclear ribonucleoprotein, RNA binding domain, RNA BINDING PROTEIN; RNA 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.

1nu4__assembly_2__model_1

Assembly 2 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

1nu4__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1nu4__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	14.22 Å
Rg (electron density)	12.78 Å
Total Rg	14.23 Å
Atom count	775
Residues	93
Excluded volume	13855 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1nu4__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1nu4__assembly_2__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`1nu4__assembly_3__model_1`	hexameric （6）	Success	4.1.3-1-20251215 (887e7ef)	View Download
4	1	`1nu4__assembly_4__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
5	1	`1nu4__assembly_5__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
6	1	`1nu4__assembly_6__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
7	1	`1nu4__assembly_7__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 (4)

Entity 1 Entity 1 polymer

Description description	U1A RNA binding domain
Molecular weight formula_weight	11209.1 kDa
Mutation mutation	Y31H,Q36R
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	1720

AVPETRPNHTIYINNLNEKIKKDELKKSLHAIFSRFGQILDILVSRSLKMRGQAFVIFKEVSSATNALRSMQGFPFYDKPMRIQYAKTDSDIIAKMK

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 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	5

Entity 3 Entity 3 non-polymer

Description description	MALONIC ACID
Molecular weight formula_weight	104.1 kDa
Source method src_method	syn
Copy count entity_count	12

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	99

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1nu4a_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.58 — Ferredoxin-like
Superfamily Superfamily superfamily	d.58.7 — RNA-binding domain, RBD, aka RNA recognition motif (RRM)
Family Family family	d.58.7.1 — Canonical RBD

Domain ID domain_id	d1nu4b_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.58 — Ferredoxin-like
Superfamily Superfamily superfamily	d.58.7 — RNA-binding domain, RBD, aka RNA recognition motif (RRM)
Family Family family	d.58.7.1 — Canonical RBD

CATH v4.4 (2 domains)

Domain ID domain_id	1nu4A00
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	70 — Alpha-Beta Plaits
Homologous superfamily homologous superfamily	330 — RRM (RNA recognition motif) domain

Domain ID domain_id	1nu4B00
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	70 — Alpha-Beta Plaits
Homologous superfamily homologous superfamily	330 — RRM (RNA recognition motif) domain

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Unit-cell length a length_a	91.819 Å
Unit-cell length b length_b	91.819 Å
Unit-cell length c length_c	120.448 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	36

Space group space_group	H 3 2
Space-group number int_tables_number	155
Crystal system crystal_system	—

Resolution resolution	1.800 Å
Low-resolution limit resolution_low	29.160 Å
R factor r_factor	0.2030
R_work r_work	0.2030
R_free r_free	0.2340

U1A RNA binding domain at 1.8 angstrom resolution reveals a pre-organized C-terminal helix

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

U1A RNA binding domain

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

1nu4__assembly_2__model_1

1nu4__assembly_2__model_1 | I(q)

1nu4__assembly_2__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

U1A RNA binding domain at 1.8 angstrom resolution reveals a pre-organized C-terminal helix

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

U1A RNA binding domain

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

1nu4__assembly_2__model_1

1nu4__assembly_2__model_1 | I(q)

1nu4__assembly_2__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)