1kca

Crystal Structure of the lambda Repressor C-terminal Domain Octamer

Method: X-RAY DIFFRACTION

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

REPRESSOR PROTEIN CI

Enterobacteria phage lambda

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 8	No other associated polymer	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 16	No other associated polymer	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	RPC1_LAMBD
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 9–109； UniProt 136–236 Author chain B； PDBConstruct 9–109； UniProt 136–236 Author chain C； PDBConstruct 9–109； UniProt 136–236 Author chain D； PDBConstruct 9–109； UniProt 136–236 Author chain E； PDBConstruct 9–109； UniProt 136–236 Author chain F； PDBConstruct 9–109； UniProt 136–236 Author chain G； PDBConstruct 9–109； UniProt 136–236 Author chain H； PDBConstruct 9–109； UniProt 136–236

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	1kca
Deposition date deposition_date	2001-11-07
Structure title title	Crystal Structure of the lambda Repressor C-terminal Domain Octamer
Keywords keywords	gene regulation, dna-binding, lambda repressor, protein oligomerization, dna-looping; 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.

1kca__assembly_1__model_1

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

Download this curve (.dat)

1kca__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1kca__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	29.82 Å
Rg (electron density)	28.72 Å
Total Rg	29.39 Å
Atom count	6160
Residues	808
Excluded volume	109550 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1kca__assembly_1__model_1`	octameric （8）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1kca__assembly_2__model_1`	hexadecameric （16）	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 (1)

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6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

Domain ID domain_id	d1kcaa_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcab_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcac_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcad_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcae_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcaf_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcag_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d1kcah_
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

CATH v4.4 (8 domains)

Domain ID domain_id	1kcaA00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaB00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaC00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaD00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaE00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaF00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaG00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	1kcaH00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

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Unit-cell length a length_a	150.090 Å
Unit-cell length b length_b	113.720 Å
Unit-cell length c length_c	95.730 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	110.26 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	32

Space group space_group	C 1 2 1
Space-group number int_tables_number	5
Crystal system crystal_system	—

Resolution resolution	2.910 Å
Low-resolution limit resolution_low	23.530 Å
R factor r_factor	—
R_work r_work	0.2270
R_free r_free	0.2670

Description description	REPRESSOR PROTEIN CI
Molecular weight formula_weight	11849.4 kDa
Source method src_method	man
Copy count entity_count	8

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D,E,F,G,H
Atom count atom_count	6160

Crystal Structure of the lambda Repressor C-terminal Domain Octamer

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

REPRESSOR PROTEIN CI

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

1kca__assembly_1__model_1

1kca__assembly_1__model_1 | I(q)

1kca__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (1)

Source organism organism	Enterobacteria phage lambda
NCBI taxonomy ID ncbi_taxonomy_id	10710
Host organism host_organism	Escherichia coli BL21(DE3)

Crystal Structure of the lambda Repressor C-terminal Domain Octamer

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

REPRESSOR PROTEIN CI

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

1kca__assembly_1__model_1

1kca__assembly_1__model_1 | I(q)

1kca__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (1)