SAXSdb — 2cio

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

PAPAIN

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	INHIBITOR OF CYSTEINE PEPTIDASE × 1 （Q868H0） GLYCEROL × 2 ACETATE ION × 3 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	PAPA1_CARPA
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–212； UniProt 134–345

INHIBITOR OF CYSTEINE PEPTIDASE

TRYPANOSOMA BRUCEI

UniProt Q868H0

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	PAPAIN × 1 （P00784） GLYCEROL × 2 ACETATE ION × 3 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q868H0_9TRYP
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–121； UniProt 1–121

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	2cio
Deposition date deposition_date	2006-03-24
Structure title title	The high resolution x-ray structure of papain complexed with fragments of the Trypanosoma brucei cysteine protease inhibitor ICP.
Keywords keywords	;HYDROLASE/INHIBITOR, COMPLEX HYDROLASE-INHIBITOR, ICP, CYSTEINE PROTEASE, INHIBITOR, TRYPANOSOMA BRUCEI, ALLERGEN, PROTEASE, THIOL PROTEASE, ZYMOGEN, HYDROLASE, HYDROLASE-INHIBITOR complex ;; 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.

2cio__assembly_1__model_1

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

Download this curve (.dat)

2cio__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2cio__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	17.36 Å
Rg (electron density)	16.20 Å
Total Rg	17.25 Å
Atom count	1714
Residues	218
Excluded volume	30216 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2cio__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 (5)

Entity 1 Entity 1 polymer

Description description	PAPAIN
Molecular weight formula_weight	23499.3 kDa
EC 编号 ec_number	3.4.22.2
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	1974

IPEYVDWRQKGAVTPVKNQGSCGSCWAFSAVVTIEGIIKIRTGNLNQYSEQELLDCDRRSYGCNGGYPWSALQLVAQYGIHYRNTYPYEGVQRYCRSREKGPYAAKTDGVRQVQPYNEGALLYSIANQPVSVVLEAAGKDFQLYRGGIFVGPCGNKVDHAVAAVGYGPNYILIKNSWGTGWGENGYIRIKRGTGNSYGVCGLYTSSFYPVKN

Entity 2 Entity 2 polymer

Description description	INHIBITOR OF CYSTEINE PEPTIDASE
Molecular weight formula_weight	13449.2 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

MSHNLFTEEDNNKTIRMVIGETFTIELESNPTTGYTWLRSGLAGTELSDCTFAIQSKFNNRAPHDNHKNHRRLLVGAGGTMVLEVKALKAGKHTLSLAYGRPWVGFNAAAKRYNIHVEATA

Source Source

Source organism organism	TRYPANOSOMA BRUCEI
NCBI taxonomy ID ncbi_taxonomy_id	5691
Host organism host_organism	ESCHERICHIA COLI BL21(DE3)

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	2

Entity 4 Entity 4 non-polymer

Description description	ACETATE ION
Molecular weight formula_weight	59.0 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	161

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d2cioa_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.3 — Cysteine proteinases
Superfamily Superfamily superfamily	d.3.1 — Cysteine proteinases
Family Family family	d.3.1.1 — Papain-like

Domain ID domain_id	d2ciob_
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.26 — ICP-like
Family Family family	b.1.26.0 — automated matches

CATH v4.4 (1 domains)

Domain ID domain_id	2cioA00
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	70 — Cathepsin B; Chain A
Homologous superfamily homologous superfamily	10 — Cysteine proteinases

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Unit-cell length a length_a	42.323 Å
Unit-cell length b length_b	46.118 Å
Unit-cell length c length_c	95.697 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	4

Space group space_group	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	95.700 Å
R factor r_factor	0.1790
R_work r_work	0.1770
R_free r_free	0.2250

The high resolution x-ray structure of papain complexed with fragments of the Trypanosoma brucei cysteine protease inhibitor ICP.

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

PAPAIN

State in the Current Structure

Other States of the Same Protein in the Database

INHIBITOR OF CYSTEINE PEPTIDASE

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

2cio__assembly_1__model_1

2cio__assembly_1__model_1 | I(q)

2cio__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 (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (2 domains)

CATH v4.4 (1 domains)

7. Citations (1)

The high resolution x-ray structure of papain complexed with fragments of the Trypanosoma brucei cysteine protease inhibitor ICP.

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

PAPAIN

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

INHIBITOR OF CYSTEINE PEPTIDASE

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

2cio__assembly_1__model_1

2cio__assembly_1__model_1 | I(q)

2cio__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 (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (2 domains)

CATH v4.4 (1 domains)

7. Citations (1)