SAXSdb — 1r5q

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

circadian oscillation regulator

Nostoc sp.

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein monomer	Monomer	Protein 1	water × 1	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 2	water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	KAIA_ANASP
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–102； UniProt 1–102

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	1r5q
Deposition date deposition_date	2003-10-12
Structure title title	Crystal Structure Analysis of Kai A from PCC7120
Keywords keywords	FOUR-HELIX-BUNDLE, GENE REGULATION; GENE REGULATION
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.

1r5q__assembly_1__model_1

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

Download this curve (.dat)

1r5q__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1r5q__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	15.00 Å
Rg (electron density)	13.70 Å
Total Rg	14.97 Å
Atom count	752
Residues	91
Excluded volume	13660 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1r5q__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1r5q__assembly_2__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 (2)

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6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d1r5qa_
Class class	a — All alpha proteins
Fold Fold fold	a.186 — KaiA/RbsU domain
Superfamily Superfamily superfamily	a.186.1 — KaiA/RbsU domain
Family Family family	a.186.1.1 — Circadian clock protein KaiA, C-terminal domain

CATH v4.4 (1 domains)

Domain ID domain_id	1r5qA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1240 — Methyltransferase, Methionine Synthase (B12-binding Domains); Chain A, domain 1
Homologous superfamily homologous superfamily	30 — KaiA/RbsU domain

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Unit-cell length a length_a	57.299 Å
Unit-cell length b length_b	57.299 Å
Unit-cell length c length_c	137.515 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	12

Space group space_group	P 65 2 2
Space-group number int_tables_number	179
Crystal system crystal_system	—

Resolution resolution	2.000 Å
Low-resolution limit resolution_low	24.420 Å
R factor r_factor	—
R_work r_work	0.2410
R_free r_free	0.2690

Description description	circadian oscillation regulator
Molecular weight formula_weight	11978.9 kDa
Source method src_method	man
Copy count entity_count	1

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	796

Crystal Structure Analysis of Kai A from PCC7120

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

circadian oscillation regulator

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

1r5q__assembly_1__model_1

1r5q__assembly_1__model_1 | I(q)

1r5q__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (1)

Source organism organism	Nostoc sp.
NCBI taxonomy ID ncbi_taxonomy_id	103690
Host organism host_organism	Escherichia coli BL21

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	38

Crystal Structure Analysis of Kai A from PCC7120

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

circadian oscillation regulator

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

1r5q__assembly_1__model_1

1r5q__assembly_1__model_1 | I(q)

1r5q__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

7. Citations (1)