3k0a

Crystal structure of the phosphorylation-site mutant S431A of the KaiC circadian clock protein

Method: X-RAY DIFFRACTION

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

Circadian clock protein kinase KaiC

Synechococcus elongatus PCC 7942

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 6	ADENOSINE-5'-TRIPHOSPHATE × 12 MAGNESIUM ION × 22 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	KAIC_SYNE7
Isoform	—
PDB entities	1, 2
Chains and sequence ranges	Author chain A； PDBConstruct 1–519； UniProt 1–519 Author chain B； PDBConstruct 1–519； UniProt 1–519 Author chain C； PDBConstruct 1–519； UniProt 1–519 Author chain D； PDBConstruct 1–519； UniProt 1–519 Author chain E； PDBConstruct 1–519； UniProt 1–519 Author chain F； PDBConstruct 1–519； UniProt 1–519

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	3k0a
Deposition date deposition_date	2009-09-24
Structure title title	Crystal structure of the phosphorylation-site mutant S431A of the KaiC circadian clock protein
Keywords keywords	;kaic, circadian clock protein, kinase, hexamer, ATP-binding, Biological rhythms, DNA-binding, Magnesium, Metal-binding, Nucleotide-binding, Phosphoprotein, Repressor, Serine/threonine-protein kinase, Transcription, Transcription regulation, Transferase ;; CIRCADIAN CLOCK PROTEIN, TRANSFERASE
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.

3k0a__assembly_1__model_1

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

Download this curve (.dat)

3k0a__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3k0a__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	42.65 Å
Rg (electron density)	41.90 Å
Total Rg	42.28 Å
Atom count	23802
Residues	2961
Excluded volume	421190 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3k0a__assembly_1__model_1`	hexameric （6）	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	Circadian clock protein kinase KaiC
Molecular weight formula_weight	58216.7 kDa
EC 编号 ec_number	2.7.11.1
Mutation mutation	S431A
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	23921

MTSAEMTSPNNNSEHQAIAKMRTMIEGFDDISHGGLPIGRSTLVSGTSGTGKTLFSIQFLYNGIIEFDEPGVFVTFEETPQDIIKNARSFGWDLAKLVDEGKLFILDASPDPEGQEVVGGFDLSALIERINYAIQKYRARRVSIDSVTSVFQQYDASSVVRRELFRLVARLKQIGATTVMTTERIEEYGPIARYGVEEFVSDNVVILRNVLEGERRRRTLEILKLRGTSHMKGEYPFTITDHGINIFPLGAMRLTQRSSNVRVSSGVVRLDEMCGGGFFKDSIILATGATGTGKTLLVSRFVENACANKERAILFAYEESRAQLLRNAYSWGMDFEEMERQNLLKIVCAYPESAGLEDHLQIIKSEINDFKPARIAIDSLSALARGVSNNAFRQFVIGVTGYAKQEEITGLFTNTSDQFMGAHSITDSHIATITDTIILLQYVEIRGEMSRAINVFKMRGSWHDKAIREFMISDKGPDIKDSFRNFERIISGSPTRITVDEKSELSRIVRGVQEKGPES

Source Source

Source organism organism	Synechococcus elongatus PCC 7942
Common name common_name	Anacystis nidulans R2
NCBI taxonomy ID ncbi_taxonomy_id	1140
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Circadian clock protein kinase KaiC
Molecular weight formula_weight	58136.8 kDa
EC 编号 ec_number	2.7.11.1
Mutation mutation	S431A
Source method src_method	man
Copy count entity_count	5

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,C,D,E,F

Source Source

Source organism organism	Synechococcus elongatus PCC 7942
Common name common_name	Anacystis nidulans R2
NCBI taxonomy ID ncbi_taxonomy_id	1140
Host organism host_organism	Escherichia coli

Entity 3 Entity 3 non-polymer

Description description	ADENOSINE-5'-TRIPHOSPHATE
Molecular weight formula_weight	507.2 kDa
Source method src_method	syn
Copy count entity_count	12

Entity 4 Entity 4 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	22

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	119

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6. Fold Classification (SCOP + CATH) 12 domains

CATH v4.4 (12 domains)

Domain ID domain_id	3k0aA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aA02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aB01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aB02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aC01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aC02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aD01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aD02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aE01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aE02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aF01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	3k0aF02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

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Unit-cell length a length_a	133.230 Å
Unit-cell length b length_b	134.960 Å
Unit-cell length c length_c	204.880 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	20

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

Resolution resolution	3.000 Å
Low-resolution limit resolution_low	30.000 Å
R factor r_factor	0.2420
R_work r_work	0.2420
R_free r_free	0.3070

Crystal structure of the phosphorylation-site mutant S431A of the KaiC circadian clock protein

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

Circadian clock protein kinase KaiC

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

3k0a__assembly_1__model_1

3k0a__assembly_1__model_1 | I(q)

3k0a__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

Source Source

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) 12 domains

CATH v4.4 (12 domains)

7. Citations (1)

Crystal structure of the phosphorylation-site mutant S431A of the KaiC circadian clock protein

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

Circadian clock protein kinase KaiC

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

3k0a__assembly_1__model_1

3k0a__assembly_1__model_1 | I(q)

3k0a__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

Source Source

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) 12 domains

CATH v4.4 (12 domains)

7. Citations (1)