1qcz

CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY

Method: X-RAY DIFFRACTION

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

N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE MUTASE

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 8	water × 8	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	PUR6_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–169； UniProt 1–169

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	1qcz
Deposition date deposition_date	1999-05-10
Structure title title	CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY
Keywords keywords	THREE-LAYER (ALPHA-BETA-ALPHA) SANDWICH, LYASE; LYASE
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.

1qcz__assembly_1__model_1

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

Download this curve (.dat)

1qcz__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1qcz__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	32.74 Å
Rg (electron density)	31.46 Å
Total Rg	31.90 Å
Atom count	9568
Residues	1272
Excluded volume	170750 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1qcz__assembly_1__model_1`	octameric （8）	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) 2 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d1qcza_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.23 — Flavodoxin-like
Superfamily Superfamily superfamily	c.23.8 — N5-CAIR mutase (phosphoribosylaminoimidazole carboxylase, PurE)
Family Family family	c.23.8.1 — N5-CAIR mutase (phosphoribosylaminoimidazole carboxylase, PurE)

CATH v4.4 (1 domains)

Domain ID domain_id	1qczA00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1970 —

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7. Citations (6)

Crystal structure of Escherichia coli PurE, an unusual mutase in the purine biosynthetic pathway.

Structure Fold.Des. (1999)

PMID: 10574791 · DOI: 10.1016/S0969-2126(00)80029-5 PRIMARY

;Evidence for the Direct Transfer of the Carboxylate of N5-Carboxyaminoimidazole Ribonucleotide (N5-CAIR) to Generate 4-Carboxy-5-Aminoimidazole Ribonucleotide Catalyzed by Escherichia coli purE, an N5-CAIR Mutase ;

Biochemistry (1999)

DOI: 10.1021/bi9827159

;Reactions Catalyzed by 5-Aminoimidazole Ribonucleotide Carboxylases from Escherichia coli Carboxylases from Escherichia coli and Gallus gallus: a Case for Divergent Catalytic Mechanisms ;

Biochemistry (1994)

;N5-Carboxyaminoimidazole Ribonucleotide: Evidence for a New Intermediate and Two New Enzymatic Activities in the de novo Purine Biosynthetic Pathway of Escherichia coli ;

Biochemistry (1994)

;Nucleotide Sequence Analysis of the purEK Operon Encoding 5'-Phosphoribosyl-5-Aminoimidazole Carboxylase of Escherichia coli K-12 ;

J.Bacteriol. (1989)

;Identification and Sequence Analysis of Escherichia coli purE and purK Genes Encoding 5'-Phosphoribosyl-5-Amino-4-Imidazole Carboxylase for de novo Purine Biosynthesis ;

J.Bacteriol. (1989)

Unit-cell length a length_a	113.040 Å
Unit-cell length b length_b	113.040 Å
Unit-cell length c length_c	49.410 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	I 4 2 2
Space-group number int_tables_number	97
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	—
R_work r_work	0.1860
R_free r_free	0.2130

Description description	N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE MUTASE
Molecular weight formula_weight	17986.9 kDa
EC 编号 ec_number	4.1.1.21
Source method src_method	man
Copy count entity_count	1

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	1380

CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY

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

N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE MUTASE

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

1qcz__assembly_1__model_1

1qcz__assembly_1__model_1 | I(q)

1qcz__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 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (6)

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	562
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	171

CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY

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

N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE MUTASE

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

1qcz__assembly_1__model_1

1qcz__assembly_1__model_1 | I(q)

1qcz__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 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (6)