SAXSdb — 9zj4

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

3C-like proteinase

Severe acute respiratory syndrome coronavirus 2

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	CHLORIDE ION × 2 ;N~2~-[(2S,4S)-3-benzyl-4-methyl-2-oxo-1,3,2lambda~5~-oxazaphospholidin-2-yl]-N-{(2S)-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propan-2-yl}-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_SARS2
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 5–309； UniProt 3264–3568

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	9zj4
Deposition date deposition_date	2025-12-04
Last revision last_revision	2026-06-10
Structure title title	Crystal structure of SARS-CoV-2 3CL protease in complex with inhibitor IKR-I-45
Keywords keywords	HYDROLASE, 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.

9zj4__assembly_1__model_1

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

Download this curve (.dat)

9zj4__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

9zj4__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	26.40 Å
Rg (electron density)	25.40 Å
Total Rg	26.23 Å
Atom count	4675
Residues	608
Excluded volume	82641 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`9zj4__assembly_1__model_1`	dimeric （2）	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 (4)

Entity 1 Entity 1 polymer

Description description	3C-like proteinase
Molecular weight formula_weight	34068.8 kDa
EC 编号 ec_number	3.4.22.69
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	2351

SNIGSGFRKMAFPSGKVEGCMVQVTCGTTTLNGLWLDDVVYCPRHVICTSEDMLNPNYEDLLIRKSNHNFLVQAGNVQLRVIGHSMQNCVLKLKVDTANPKTPKYKFVRIQPGQTFSVLACYNGSPSGVYQCAMRPNFTIKGSFLNGSCGSVGFNIDYDCVSFCYMHHMELPTGVHAGTDLEGNFYGPFVDRQTAQAAGTDTTITVNVLAWLYAAVINGDRWFLNRFTTTLNDFNLVAMKYNYEPLTQDHVDILGPLSAQTGIAVLDMCASLKELLQNGMNGRTILGSALLEDEFTPFDVVRQCSGVTF

Source Source

Source organism organism	Severe acute respiratory syndrome coronavirus 2
NCBI taxonomy ID ncbi_taxonomy_id	2697049
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 2 Entity 2 non-polymer

Description description	CHLORIDE ION
Molecular weight formula_weight	35.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 3 Entity 3 non-polymer

Description description	;N~2~-[(2S,4S)-3-benzyl-4-methyl-2-oxo-1,3,2lambda~5~-oxazaphospholidin-2-yl]-N-{(2S)-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propan-2-yl}-L-leucinamide ;
Molecular weight formula_weight	478.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	13

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Unit-cell length a length_a	111.258 Å
Unit-cell length b length_b	54.912 Å
Unit-cell length c length_c	46.795 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	101.89 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	4

Space group space_group	C 1 2 1
Space-group number int_tables_number	5
Crystal system crystal_system	—

Resolution resolution	2.440 Å
Low-resolution limit resolution_low	49.030 Å
R factor r_factor	0.2132
R_work r_work	0.2106
R_free r_free	0.2656

Crystal structure of SARS-CoV-2 3CL protease in complex with inhibitor IKR-I-45

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

9zj4__assembly_1__model_1

9zj4__assembly_1__model_1 | I(q)

9zj4__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 (4)

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 water

7. Citations (1)

Crystal structure of SARS-CoV-2 3CL protease in complex with inhibitor IKR-I-45

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

9zj4__assembly_1__model_1

9zj4__assembly_1__model_1 | I(q)

9zj4__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 (4)

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 water

7. Citations (1)