SAXSdb — 6xa4

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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 heterocomplex	Heteromer	Protein 4	inhibitor UAW241 × 2 GLYCEROL × 2 water × 4	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 3–308； UniProt 3264–3569

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	6xa4
Deposition date deposition_date	2020-06-03
Structure title title	Crystal structure of the SARS-CoV-2 (COVID-19) main protease in complex with UAW241
Keywords keywords	;COVID, COVID19, COVID-19, SARS, SARS COV2, COV, NCOV 19, CORONAVIRUS, MAIN PROTEASE, 3CL, MPRO, PRO, VIRAL PROTEIN, GC376, calpain inhibitor II, leupeptin, calpain, aldehyde, GC-376, 3cl-like, a-ketoamide, alpheketoamide, alpha, ketoamide, PEPTIDOMIMETIC, PROTEASE, CYSTEINE, 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.

6xa4__assembly_1__model_1

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

Download this curve (.dat)

6xa4__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6xa4__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	26.51 Å
Rg (electron density)	25.43 Å
Total Rg	26.30 Å
Atom count	4752
Residues	612
Excluded volume	84705 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6xa4__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 (4)

Entity 1 Entity 1 polymer

Description description	3C-like proteinase
Molecular weight formula_weight	34094.9 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	2548

HMSGFRKMAFPSGKVEGCMVQVTCGTTTLNGLWLDDVVYCPRHVICTSEDMLNPNYEDLLIRKSNHNFLVQAGNVQLRVIGHSMQNCVLKLKVDTANPKTPKYKFVRIQPGQTFSVLACYNGSPSGVYQCAMRPNFTIKGSFLNGSCGSVGFNIDYDCVSFCYMHHMELPTGVHAGTDLEGNFYGPFVDRQTAQAAGTDTTITVNVLAWLYAAVINGDRWFLNRFTTTLNDFNLVAMKYNYEPLTQDHVDILGPLSAQTGIAVLDMCASLKELLQNGMNGRTILGSALLEDEFTPFDVVRQCSGVTFQ

Source Source

Source organism organism	Severe acute respiratory syndrome coronavirus 2
Common name common_name	2019-nCoV
NCBI taxonomy ID ncbi_taxonomy_id	2697049
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	inhibitor UAW241
Molecular weight formula_weight	387.6 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

XLLX

Entity 3 Entity 3 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 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	158

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6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

Domain ID domain_id	6xa4A01
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	6xa4A02
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	6xa4A03
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	113.538 Å
Unit-cell length b length_b	54.204 Å
Unit-cell length c length_c	45.414 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	100.71 °
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	1.650 Å
Low-resolution limit resolution_low	38.540 Å
R factor r_factor	0.2002
R_work r_work	0.1982
R_free r_free	0.2393

Crystal structure of the SARS-CoV-2 (COVID-19) main protease in complex with UAW241

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

6xa4__assembly_1__model_1

6xa4__assembly_1__model_1 | I(q)

6xa4__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 polymer

Polymer Polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)

Crystal structure of the SARS-CoV-2 (COVID-19) main protease in complex with UAW241

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

6xa4__assembly_1__model_1

6xa4__assembly_1__model_1 | I(q)

6xa4__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 polymer

Polymer Polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)