SAXSdb — 4a1g

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

MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1

HOMO SAPIENS

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	PROTEIN CASC5 × 1 （Q8NG31） water × 1	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	PROTEIN CASC5 × 1 （Q8NG31） water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 2	PROTEIN CASC5 × 1 （Q8NG31） water × 2	Consistent with protein count
4	Protein heterocomplex	Heteromer	Protein 2	PROTEIN CASC5 × 1 （Q8NG31） water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	BUB1_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 3–152； UniProt 1–150 Author chain B； PDBConstruct 3–152； UniProt 1–150 Author chain C； PDBConstruct 3–152； UniProt 1–150 Author chain D； PDBConstruct 3–152； UniProt 1–150

PROTEIN CASC5

HOMO SAPIENS

UniProt Q8NG31

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1 × 1 （O43683） water × 1	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1 × 1 （O43683） water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 2	MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1 × 1 （O43683） water × 2	Consistent with protein count
4	Protein heterocomplex	Heteromer	Protein 2	MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1 × 1 （O43683） water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CASC5_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain E； PDBConstruct 3–53； UniProt 150–200 Author chain F； PDBConstruct 3–53； UniProt 150–200 Author chain G； PDBConstruct 3–53； UniProt 150–200 Author chain H； PDBConstruct 3–53； UniProt 150–200

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	4a1g
Deposition date deposition_date	2011-09-15
Structure title title	The crystal structure of the human Bub1 TPR domain in complex with the KI motif of Knl1
Keywords keywords	CELL CYCLE, TRANSFERASE, SPINDLE ASSEMBLY CHECKPOINT, MITOSIS, TPR REPEAT, KNL1, KMN NETWORK; CELL CYCLE
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.

4a1g__assembly_1__model_1

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

Download this curve (.dat)

4a1g__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4a1g__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	18.11 Å
Rg (electron density)	16.91 Å
Total Rg	17.84 Å
Atom count	1309
Residues	158
Excluded volume	23157 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4a1g__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`4a1g__assembly_2__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`4a1g__assembly_3__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
4	1	`4a1g__assembly_4__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 (3)

Entity 1 Entity 1 polymer

Description description	MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1
Molecular weight formula_weight	18121.3 kDa
EC 编号 ec_number	2.7.11.1
Source method src_method	man
Copy count entity_count	4

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D
Atom count atom_count	5497

GPMDTPENVLQMLEAHMQSYKGNDPLGEWERYIQWVEENFPENKEYLITLLEHLMKEFLDKKKYHNDPRFISYCLKFAEYNSDLHQFFEFLYNHGIGTLSSPLYIAWAGHLEAQGELQHASAVLQRGIQNQAEPREFLQQQYRLFQTRLTET

Source Source

Source organism organism	HOMO SAPIENS
Common name common_name	HUMAN
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	ESCHERICHIA COLI

Entity 2 Entity 2 polymer

Description description	PROTEIN CASC5
Molecular weight formula_weight	5911.8 kDa
Source method src_method	man
Copy count entity_count	4

Polymer Polymer

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

GPQMDLTSSHTVMITKGLLDNPISEKSTKIDTTSFLANLKLHTEDSRMKKEVN

Source Source

Source organism organism	HOMO SAPIENS
Common name common_name	HUMAN
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	ESCHERICHIA COLI

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	120

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6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

Domain ID domain_id	4a1gA00
Class class	1 — Mainly Alpha
Architecture architecture	25 — Alpha Horseshoe
Topology topology	40 — Serine Threonine Protein Phosphatase 5, Tetratricopeptide repeat
Homologous superfamily homologous superfamily	430 —

Domain ID domain_id	4a1gB00
Class class	1 — Mainly Alpha
Architecture architecture	25 — Alpha Horseshoe
Topology topology	40 — Serine Threonine Protein Phosphatase 5, Tetratricopeptide repeat
Homologous superfamily homologous superfamily	430 —

Domain ID domain_id	4a1gC00
Class class	1 — Mainly Alpha
Architecture architecture	25 — Alpha Horseshoe
Topology topology	40 — Serine Threonine Protein Phosphatase 5, Tetratricopeptide repeat
Homologous superfamily homologous superfamily	430 —

Domain ID domain_id	4a1gD00
Class class	1 — Mainly Alpha
Architecture architecture	25 — Alpha Horseshoe
Topology topology	40 — Serine Threonine Protein Phosphatase 5, Tetratricopeptide repeat
Homologous superfamily homologous superfamily	430 —

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Unit-cell length a length_a	59.279 Å
Unit-cell length b length_b	130.969 Å
Unit-cell length c length_c	74.956 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	110.17 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	8

Space group space_group	P 1 21 1
Space-group number int_tables_number	4
Crystal system crystal_system	—

Resolution resolution	2.600 Å
Low-resolution limit resolution_low	61.983 Å
R factor r_factor	0.1889
R_work r_work	0.1859
R_free r_free	0.2436

The crystal structure of the human Bub1 TPR domain in complex with the KI motif of Knl1

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

MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1

State in the Current Structure

Other States of the Same Protein in the Database

PROTEIN CASC5

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

4a1g__assembly_1__model_1

4a1g__assembly_1__model_1 | I(q)

4a1g__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

Source Source

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

7. Citations (1)

The crystal structure of the human Bub1 TPR domain in complex with the KI motif of Knl1

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

MITOTIC CHECKPOINT SERINE/THREONINE-PROTEIN KINASE BUB1

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

PROTEIN CASC5

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

4a1g__assembly_1__model_1

4a1g__assembly_1__model_1 | I(q)

4a1g__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

Source Source

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

CATH v4.4 (4 domains)

7. Citations (1)