SAXSdb — 1qk5

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

HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE

TOXOPLASMA GONDII

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	XANTHOSINE-5'-MONOPHOSPHATE × 4 PYROPHOSPHATE 2- × 4 MAGNESIUM ION × 8 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HGXR_TOXGO
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 4–233； UniProt 1–230 Author chain B； PDBConstruct 4–233； UniProt 1–230

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	1qk5
Deposition date deposition_date	1999-07-09
Structure title title	TOXOPLASMA GONDII HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE WITH XMP, PYROPHOSPHATE AND TWO MG2+ IONS
Keywords keywords	TRANSFERASE, GLYCOSYLTRANSFERASE, PURINE SALVAGE; TRANSFERASE
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.

1qk5__assembly_1__model_1

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

Download this curve (.dat)

1qk5__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1qk5__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	28.36 Å
Rg (electron density)	26.97 Å
Total Rg	27.98 Å
Atom count	7084
Residues	864
Excluded volume	126750 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1qk5__assembly_1__model_1`	tetrameric （4）	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 (5)

Entity 1 Entity 1 polymer

Description description	HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE
Molecular weight formula_weight	26661.5 kDa
EC 编号 ec_number	2.4.2.8
Mutation mutation	YES
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	3724

GSHMASKPIEDYGKGKGRIEPMYIPDNTFYNADDFLVPPHCKPYIDKILLPGGLVKDRVEKLAYDIHRTYFGEELHIICILKGSRGFFNLLIDYLATIQKYSGRESSVPPFFEHYVRLKSYQNDNSTGQLTVLSDDLSIFRDKHVLIVEDIVATGFTLTEFGERLKAVGPKSMRIATLVEKRTDRSNSLKGDFVGFSIEDVWIVGCCYDFNEMFRDFDHVAVLSDAARKKFEK

Source Source

Source organism organism	TOXOPLASMA GONDII
NCBI taxonomy ID ncbi_taxonomy_id	383379
Host organism host_organism	ESCHERICHIA COLI

Entity 2 Entity 2 non-polymer

Description description	XANTHOSINE-5'-MONOPHOSPHATE
Molecular weight formula_weight	365.2 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 non-polymer

Description description	PYROPHOSPHATE 2-
Molecular weight formula_weight	176.0 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 4 Entity 4 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	182

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1qk5a_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.61 — PRTase-like
Superfamily Superfamily superfamily	c.61.1 — PRTase-like
Family Family family	c.61.1.1 — Phosphoribosyltransferases (PRTases)

Domain ID domain_id	d1qk5b_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.61 — PRTase-like
Superfamily Superfamily superfamily	c.61.1 — PRTase-like
Family Family family	c.61.1.1 — Phosphoribosyltransferases (PRTases)

CATH v4.4 (2 domains)

Domain ID domain_id	1qk5A00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2020 —

Domain ID domain_id	1qk5B00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2020 —

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Unit-cell length a length_a	55.208 Å
Unit-cell length b length_b	112.255 Å
Unit-cell length c length_c	144.280 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	C 2 2 21
Space-group number int_tables_number	20
Crystal system crystal_system	—

Resolution resolution	1.600 Å
Low-resolution limit resolution_low	13.000 Å
R factor r_factor	—
R_work r_work	0.2335
R_free r_free	0.2610

TOXOPLASMA GONDII HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE WITH XMP, PYROPHOSPHATE AND TWO MG2+ IONS

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

HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE

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

1qk5__assembly_1__model_1

1qk5__assembly_1__model_1 | I(q)

1qk5__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 (5)

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 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (3)

TOXOPLASMA GONDII HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE WITH XMP, PYROPHOSPHATE AND TWO MG2+ IONS

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

HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE

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

1qk5__assembly_1__model_1

1qk5__assembly_1__model_1 | I(q)

1qk5__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 (5)

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 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (3)