3d23

Main protease of HCoV-HKU1

Method: X-RAY DIFFRACTION

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

3C-like proteinase

Human coronavirus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 8	;N-[(5-METHYLISOXAZOL-3-YL)CARBONYL]ALANYL-L-VALYL-N~1~-((1R,2Z)-4-(BENZYLOXY)-4-OXO-1-{[(3R)-2-OXOPYRROLIDIN-3-YL]METHYL}BUT-2-ENYL)-L-LEUCINAMIDE ; × 4 water × 4	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 4	;N-[(5-METHYLISOXAZOL-3-YL)CARBONYL]ALANYL-L-VALYL-N~1~-((1R,2Z)-4-(BENZYLOXY)-4-OXO-1-{[(3R)-2-OXOPYRROLIDIN-3-YL]METHYL}BUT-2-ENYL)-L-LEUCINAMIDE ; × 2 water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 4	;N-[(5-METHYLISOXAZOL-3-YL)CARBONYL]ALANYL-L-VALYL-N~1~-((1R,2Z)-4-(BENZYLOXY)-4-OXO-1-{[(3R)-2-OXOPYRROLIDIN-3-YL]METHYL}BUT-2-ENYL)-L-LEUCINAMIDE ; × 2 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	R1AB_CVHN1
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 3–302； UniProt 3335–3634 Author chain B； PDBConstruct 3–302； UniProt 3335–3634 Author chain C； PDBConstruct 3–302； UniProt 3335–3634 Author chain D； PDBConstruct 3–302； UniProt 3335–3634

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	3d23
Deposition date deposition_date	2008-05-07
Structure title title	Main protease of HCoV-HKU1
Keywords keywords	;main protease, ATP-binding, Endonuclease, Exonuclease, Helicase, Membrane, Metal-binding, Nuclease, Nucleotide-binding, Nucleotidyltransferase, Protease, RNA replication, RNA-binding, RNA-directed RNA polymerase, Thiol protease, Transferase, Transmembrane, Zinc-finger, HYDROLASE-HYDROLASE INHIBITOR complex ;; HYDROLASE/HYDROLASE INHIBITOR
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.

3d23__assembly_1__model_1

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

Download this curve (.dat)

3d23__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3d23__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	40.53 Å
Rg (electron density)	40.45 Å
Total Rg	40.73 Å
Atom count	9362
Residues	1208
Excluded volume	167560 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3d23__assembly_1__model_1`	octameric （8）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3d23__assembly_2__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`3d23__assembly_3__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 (3)

Entity 1 Entity 1 polymer

Description description	3C-like proteinase
Molecular weight formula_weight	33009.7 kDa
EC 编号 ec_number	3.4.22.-
Source method src_method	man
Copy count entity_count	4

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,A,C,D
Atom count atom_count	9579

ASSGIVKMVSPTSKIEPCIVSVTYGSMTLNGLWLDDKVYCPRHVICSSSNMNEPDYSALLCRVTLGDFTIMSGRMSLTVVSYQMQGCQLVLTVSLQNPYTPKYTFGNVKPGETFTVLAAYNGRPQGAFHVTMRSSYTIKGSFLCGSCGSVGYVLTGDSVKFVYMHQLELSTGCHTGTDFTGNFYGPYRDAQVVQLPVKDYVQTVNVIAWLYAAILNNCAWFVQNDVCSTEDFNVWAMANGFSQVKADLVLDALASMTGVSIETLLAAIKRLYMGFQGRQILGSCTFEDELAPSDVYQQLAGV

Source Source

Source organism organism	Human coronavirus
Common name common_name	HCoV-HKU1
NCBI taxonomy ID ncbi_taxonomy_id	443239
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	;N-[(5-METHYLISOXAZOL-3-YL)CARBONYL]ALANYL-L-VALYL-N~1~-((1R,2Z)-4-(BENZYLOXY)-4-OXO-1-{[(3R)-2-OXOPYRROLIDIN-3-YL]METHYL}BUT-2-ENYL)-L-LEUCINAMIDE ;
Molecular weight formula_weight	680.8 kDa
Source method src_method	syn
Copy count entity_count	4

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	H,F,E,G

XAVLXX

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	208

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6. Fold Classification (SCOP + CATH) 18 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d3d23a1
Class class	b — All beta proteins
Fold Fold fold	b.47 — Trypsin-like serine proteases
Superfamily Superfamily superfamily	b.47.1 — Trypsin-like serine proteases
Family Family family	b.47.1.4 — Viral cysteine protease of trypsin fold

Domain ID domain_id	d3d23a2
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	d3d23b1
Class class	b — All beta proteins
Fold Fold fold	b.47 — Trypsin-like serine proteases
Superfamily Superfamily superfamily	b.47.1 — Trypsin-like serine proteases
Family Family family	b.47.1.4 — Viral cysteine protease of trypsin fold

Domain ID domain_id	d3d23b2
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	d3d23c_
Class class	b — All beta proteins
Fold Fold fold	b.47 — Trypsin-like serine proteases
Superfamily Superfamily superfamily	b.47.1 — Trypsin-like serine proteases
Family Family family	b.47.1.4 — Viral cysteine protease of trypsin fold

Domain ID domain_id	d3d23d_
Class class	b — All beta proteins
Fold Fold fold	b.47 — Trypsin-like serine proteases
Superfamily Superfamily superfamily	b.47.1 — Trypsin-like serine proteases
Family Family family	b.47.1.4 — Viral cysteine protease of trypsin fold

CATH v4.4 (12 domains)

Domain ID domain_id	3d23A01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23A02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23A03
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1840 — main proteinase (3clpro) structure, domain 3
Homologous superfamily homologous superfamily	10 — main proteinase (3clpro) structure, domain 3

Domain ID domain_id	3d23B01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23B02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23B03
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1840 — main proteinase (3clpro) structure, domain 3
Homologous superfamily homologous superfamily	10 — main proteinase (3clpro) structure, domain 3

Domain ID domain_id	3d23C01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23C02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23C03
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1840 — main proteinase (3clpro) structure, domain 3
Homologous superfamily homologous superfamily	10 — main proteinase (3clpro) structure, domain 3

Domain ID domain_id	3d23D01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23D02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	3d23D03
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1840 — main proteinase (3clpro) structure, domain 3
Homologous superfamily homologous superfamily	10 — main proteinase (3clpro) structure, domain 3

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Unit-cell length a length_a	91.770 Å
Unit-cell length b length_b	91.770 Å
Unit-cell length c length_c	187.914 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
Space-group number int_tables_number	76
Crystal system crystal_system	—

Resolution resolution	2.500 Å
Low-resolution limit resolution_low	50.000 Å
R factor r_factor	0.2320
R_work r_work	0.2290
R_free r_free	0.2850

Main protease of HCoV-HKU1

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

3C-like proteinase

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

3d23__assembly_1__model_1

3d23__assembly_1__model_1 | I(q)

3d23__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) 18 domains

SCOP 2.08 (6 domains)

CATH v4.4 (12 domains)

7. Citations (1)

Main protease of HCoV-HKU1

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

3C-like proteinase

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

3d23__assembly_1__model_1

3d23__assembly_1__model_1 | I(q)

3d23__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) 18 domains

SCOP 2.08 (6 domains)

CATH v4.4 (12 domains)

7. Citations (1)