SAXSdb — 3a5u

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

Single-stranded DNA-binding protein

Mycobacterium smegmatis

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Homooligomer	Protein 4 DNA 2	DNA (31-MER) × 2 water × 6	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SSB_MYCS2
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–130； UniProt 1–130 Author chain B； PDBConstruct 1–130； UniProt 1–130

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	3a5u
Deposition date deposition_date	2009-08-12
Structure title title	Promiscuity and specificity in DNA binding to SSB: Insights from the structure of the Mycobacterium smegmatis SSB-ssDNA complex
Keywords keywords	DNA binding protein, DNA damage, DNA repair, DNA replication, DNA-binding; DNA 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.

3a5u__assembly_1__model_1

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

Download this curve (.dat)

3a5u__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3a5u__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.99 Å
Rg (electron density)	23.37 Å
Total Rg	24.16 Å
Atom count	4326
Residues	522
Excluded volume	73076 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3a5u__assembly_1__model_1`	hexameric （6）	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	Single-stranded DNA-binding protein
Molecular weight formula_weight	14042.7 kDa
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	2236

MAGDTTITVVGNLTADPELRFTPSGAAVANFTVASTPRMFDRQSGEWKDGEALFLRCNIWREAAENVAESLTRGSRVIVTGRLKQRSFETREGEKRTVVEVEVDEIGPSLRYATAKVNKASRSGGGGGGF

Source Source

Source organism organism	Mycobacterium smegmatis
NCBI taxonomy ID ncbi_taxonomy_id	246196
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	DNA (31-MER)
Molecular weight formula_weight	8919.7 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	C

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	73

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3a5ua_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.4 — Nucleic acid-binding proteins
Family Family family	b.40.4.3 — Single strand DNA-binding domain, SSB

Domain ID domain_id	d3a5ub_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.4 — Nucleic acid-binding proteins
Family Family family	b.40.4.3 — Single strand DNA-binding domain, SSB

CATH v4.4 (2 domains)

Domain ID domain_id	3a5uA00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	140 — Nucleic acid-binding proteins

Domain ID domain_id	3a5uB00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	140 — Nucleic acid-binding proteins

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Unit-cell length a length_a	112.330 Å
Unit-cell length b length_b	112.330 Å
Unit-cell length c length_c	48.490 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	P 43 21 2
Space-group number int_tables_number	96
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	30.000 Å
R factor r_factor	0.2404
R_work r_work	0.2384
R_free r_free	0.2831

Promiscuity and specificity in DNA binding to SSB: Insights from the structure of the Mycobacterium smegmatis SSB-ssDNA complex

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

Single-stranded DNA-binding protein

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

3a5u__assembly_1__model_1

3a5u__assembly_1__model_1 | I(q)

3a5u__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 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 (5)

Promiscuity and specificity in DNA binding to SSB: Insights from the structure of the Mycobacterium smegmatis SSB-ssDNA complex

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

Single-stranded DNA-binding protein

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

3a5u__assembly_1__model_1

3a5u__assembly_1__model_1 | I(q)

3a5u__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 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 (5)