1a9c

GTP CYCLOHYDROLASE I (C110S MUTANT) IN COMPLEX WITH GTP

Method: X-RAY DIFFRACTION

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

GTP CYCLOHYDROLASE I

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 10	GUANOSINE-5'-TRIPHOSPHATE × 10 water × 10	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 10	GUANOSINE-5'-TRIPHOSPHATE × 10 water × 10	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	GCH1_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–221； UniProt 1–221 Author chain B； PDBConstruct 1–221； UniProt 1–221 Author chain C； PDBConstruct 1–221； UniProt 1–221 Author chain D； PDBConstruct 1–221； UniProt 1–221 Author chain E； PDBConstruct 1–221； UniProt 1–221 Author chain F； PDBConstruct 1–221； UniProt 1–221 Author chain G； PDBConstruct 1–221； UniProt 1–221 Author chain H； PDBConstruct 1–221； UniProt 1–221 Author chain I； PDBConstruct 1–221； UniProt 1–221 Author chain J； PDBConstruct 1–221； UniProt 1–221 Author chain K； PDBConstruct 1–221； UniProt 1–221 Author chain L； PDBConstruct 1–221； UniProt 1–221 Author chain M； PDBConstruct 1–221； UniProt 1–221 Author chain N； PDBConstruct 1–221； UniProt 1–221 Author chain O； PDBConstruct 1–221； UniProt 1–221

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	1a9c
Deposition date deposition_date	1998-04-04
Structure title title	GTP CYCLOHYDROLASE I (C110S MUTANT) IN COMPLEX WITH GTP
Keywords keywords	HYDROLASE, GTP, PURINE HYDROLYSIS, PTERINE SYNTHESIS, TETRAHYDROBIOPTERIN; HYDROLASE
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.

1a9c__assembly_1__model_1

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

Download this curve (.dat)

1a9c__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1a9c__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	37.92 Å
Rg (electron density)	37.15 Å
Total Rg	37.72 Å
Atom count	21690
Residues	2210
Excluded volume	313320 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1a9c__assembly_1__model_1`	decameric （10）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1a9c__assembly_2__model_1`	decameric （10）	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	GTP CYCLOHYDROLASE I
Molecular weight formula_weight	24717.4 kDa
EC 编号 ec_number	3.5.4.16
Mutation mutation	C110S
Source method src_method	man
Copy count entity_count	15

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D,E,F,G,H,I,J,K,L,M,N,O
Atom count atom_count	33165

PSLSKEAALVHEALVARGLETPLRPPVHEMDNETRKSLIAGHMTEIMQLLNLDLADDSLMETPHRIAKMYVDEIFSGLDYANFPKITLIENKMKVDEMVTVRDITLTSTSEHHFVTIDGKATVAYIPKDSVIGLSKINRIVQFFAQRPQVQERLTQQILIALQTLLGTNNVAVSIDAVHYCVKARGIRDATSATTTTSLGGLFKSSQNTRHEFLRAVRHHN

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	562
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	GUANOSINE-5'-TRIPHOSPHATE
Molecular weight formula_weight	523.2 kDa
Source method src_method	syn
Copy count entity_count	15

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	210

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6. Fold Classification (SCOP + CATH) 45 domains

SCOP 2.08 (15 domains)

Domain ID domain_id	d1a9ca_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cb_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cc_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cd_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9ce_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cf_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cg_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9ch_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9ci_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cj_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9ck_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cl_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cm_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9cn_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

Domain ID domain_id	d1a9co_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.96 — T-fold
Superfamily Superfamily superfamily	d.96.1 — Tetrahydrobiopterin biosynthesis enzymes-like
Family Family family	d.96.1.1 — GTP cyclohydrolase I

CATH v4.4 (30 domains)

Domain ID domain_id	1a9cA01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cA02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cB01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cB02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cC01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cC02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cD01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cD02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cE01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cE02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cF01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cF02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cG01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cG02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cH01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cH02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cI01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cI02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cJ01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cJ02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cK01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cK02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cL01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cL02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cM01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cM02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cN01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cN02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

Domain ID domain_id	1a9cO01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	286 — GTP Cyclohydrolase I; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, N-terminal domain

Domain ID domain_id	1a9cO02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1130 — GTP Cyclohydrolase I, domain 2
Homologous superfamily homologous superfamily	10 — GTP cyclohydrolase I, C-terminal domain/NADPH-dependent 7-cyano-7-deazaguanine reductase, N-terminal domain

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Unit-cell length a length_a	313.900 Å
Unit-cell length b length_b	226.800 Å
Unit-cell length c length_c	131.400 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	120

Space group space_group	C 2 2 21
Space-group number int_tables_number	20
Crystal system crystal_system	—

Resolution resolution	2.900 Å
Low-resolution limit resolution_low	8.000 Å
R factor r_factor	0.2060
R_work r_work	0.2060
R_free r_free	0.2880

GTP CYCLOHYDROLASE I (C110S MUTANT) IN COMPLEX WITH GTP

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

GTP CYCLOHYDROLASE I

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

1a9c__assembly_1__model_1

1a9c__assembly_1__model_1 | I(q)

1a9c__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 45 domains

SCOP 2.08 (15 domains)

CATH v4.4 (30 domains)

7. Citations (5)

GTP CYCLOHYDROLASE I (C110S MUTANT) IN COMPLEX WITH GTP

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

GTP CYCLOHYDROLASE I

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

1a9c__assembly_1__model_1

1a9c__assembly_1__model_1 | I(q)

1a9c__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 45 domains

SCOP 2.08 (15 domains)

CATH v4.4 (30 domains)

7. Citations (5)