SAXSdb — 1q87

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

39 kDa initiator binding protein

Trichomonas vaginalis

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	Q95VR4_TRIVA
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–215； UniProt 127–341 Author chain B； PDBConstruct 1–215； UniProt 127–341

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	1q87
Deposition date deposition_date	2003-08-20
Structure title title	Crystal structure of the C-domain of the T.vaginalis Inr binding protein, IBP39 (tetragonal form)
Keywords keywords	Initiator, Inr, Initiator binding protein, core promoter, DNA BINDING PROTEIN; 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.

1q87__assembly_2__model_1

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

Download this curve (.dat)

1q87__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1q87__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	18.51 Å
Rg (electron density)	17.50 Å
Total Rg	18.53 Å
Atom count	1560
Residues	193
Excluded volume	27947 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1q87__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1q87__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

SCOP 2.08 (4 domains)

Domain ID domain_id	d1q87a1
Class class	e — Multi-domain proteins (alpha and beta)
Fold Fold fold	e.47 — 39 kda initiator binding protein, IBP39, C-terminal domains
Superfamily Superfamily superfamily	e.47.1 — 39 kda initiator binding protein, IBP39, C-terminal domains
Family Family family	e.47.1.1 — 39 kda initiator binding protein, IBP39, C-terminal domains

Domain ID domain_id	d1q87a2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d1q87b1
Class class	e — Multi-domain proteins (alpha and beta)
Fold Fold fold	e.47 — 39 kda initiator binding protein, IBP39, C-terminal domains
Superfamily Superfamily superfamily	e.47.1 — 39 kda initiator binding protein, IBP39, C-terminal domains
Family Family family	e.47.1.1 — 39 kda initiator binding protein, IBP39, C-terminal domains

Domain ID domain_id	d1q87b2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

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Unit-cell length a length_a	76.420 Å
Unit-cell length b length_b	76.420 Å
Unit-cell length c length_c	157.620 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 41 21 2
Space-group number int_tables_number	92
Crystal system crystal_system	—

Resolution resolution	2.320 Å
Low-resolution limit resolution_low	65.000 Å
R factor r_factor	0.2150
R_work r_work	0.2150
R_free r_free	0.2740

Description description	39 kDa initiator binding protein
Molecular weight formula_weight	25727.2 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	3115

Crystal structure of the C-domain of the T.vaginalis Inr binding protein, IBP39 (tetragonal form)

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

39 kDa initiator 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

1q87__assembly_2__model_1

1q87__assembly_2__model_1 | I(q)

1q87__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (4 domains)

7. Citations (1)

Source organism organism	Trichomonas vaginalis
NCBI taxonomy ID ncbi_taxonomy_id	5722
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	61

Crystal structure of the C-domain of the T.vaginalis Inr binding protein, IBP39 (tetragonal form)

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

39 kDa initiator 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

1q87__assembly_2__model_1

1q87__assembly_2__model_1 | I(q)

1q87__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (4 domains)

7. Citations (1)