SAXSdb — 1pk1

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

Polyhomeotic-proximal chromatin protein

Drosophila melanogaster

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Sex comb on midleg CG9495-PA × 1 （Q9VHA0） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	Sex comb on midleg CG9495-PA × 1 （Q9VHA0） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	PHP_DROME
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 6–81； UniProt 1502–1577 Author chain C； PDBConstruct 6–81； UniProt 1502–1577

Sex comb on midleg CG9495-PA

Drosophila melanogaster

UniProt Q9VHA0

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Polyhomeotic-proximal chromatin protein × 1 （P39769） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	Polyhomeotic-proximal chromatin protein × 1 （P39769） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SCM_DROME
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 6–82； UniProt 795–871 Author chain D； PDBConstruct 6–82； UniProt 795–871

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	1pk1
Deposition date deposition_date	2003-06-04
Structure title title	Hetero SAM domain structure of Ph and Scm.
Keywords keywords	Hetero SAM domain, polymers, transcriptional repression, transcription repression; transcription repression
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.

1pk1__assembly_1__model_1

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

Download this curve (.dat)

1pk1__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1pk1__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	17.17 Å
Rg (electron density)	16.15 Å
Total Rg	17.08 Å
Atom count	1096
Residues	136
Excluded volume	19750 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1pk1__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1pk1__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 (3)

Entity 1 Entity 1 polymer

Description description	Polyhomeotic-proximal chromatin protein
Molecular weight formula_weight	10319.5 kDa
Mutation mutation	L1565R
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,C
Atom count atom_count	2343

MEKTRVNGTDRPPISSWSVDDVSNFIRELPGCQDYVDDFIQQEIDGQALLLLKEKHLVNAMGMKLGPARKIVAKVESIKEVRDHHHHHH

Source Source

Source organism organism	Drosophila melanogaster
Common name common_name	fruit fly
NCBI taxonomy ID ncbi_taxonomy_id	7227
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Sex comb on midleg CG9495-PA
Molecular weight formula_weight	10410.0 kDa
Mutation mutation	L841R, M846R
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MEKTRANSHLRSQPIDWTIEEVIQYIESNDNSLAVHGDLFRKHEIDGKALLRLNSERMMKYMGLKLGPALKICNLVNKVNGRDHHHHHH

Source Source

Source organism organism	Drosophila melanogaster
Common name common_name	fruit fly
NCBI taxonomy ID ncbi_taxonomy_id	7227
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	193

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1pk1a1
Class class	a — All alpha proteins
Fold Fold fold	a.60 — SAM domain-like
Superfamily Superfamily superfamily	a.60.1 — SAM/Pointed domain
Family Family family	a.60.1.2 — SAM (sterile alpha motif) domain

Domain ID domain_id	d1pk1b1
Class class	a — All alpha proteins
Fold Fold fold	a.60 — SAM domain-like
Superfamily Superfamily superfamily	a.60.1 — SAM/Pointed domain
Family Family family	a.60.1.2 — SAM (sterile alpha motif) domain

Domain ID domain_id	d1pk1c_
Class class	a — All alpha proteins
Fold Fold fold	a.60 — SAM domain-like
Superfamily Superfamily superfamily	a.60.1 — SAM/Pointed domain
Family Family family	a.60.1.2 — SAM (sterile alpha motif) domain

Domain ID domain_id	d1pk1d_
Class class	a — All alpha proteins
Fold Fold fold	a.60 — SAM domain-like
Superfamily Superfamily superfamily	a.60.1 — SAM/Pointed domain
Family Family family	a.60.1.0 — automated matches

CATH v4.4 (4 domains)

Domain ID domain_id	1pk1A00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	150 — DNA polymerase; domain 1
Homologous superfamily homologous superfamily	50 — Transcription Factor, Ets-1

Domain ID domain_id	1pk1B00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	150 — DNA polymerase; domain 1
Homologous superfamily homologous superfamily	50 — Transcription Factor, Ets-1

Domain ID domain_id	1pk1C00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	150 — DNA polymerase; domain 1
Homologous superfamily homologous superfamily	50 — Transcription Factor, Ets-1

Domain ID domain_id	1pk1D00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	150 — DNA polymerase; domain 1
Homologous superfamily homologous superfamily	50 — Transcription Factor, Ets-1

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Unit-cell length a length_a	30.277 Å
Unit-cell length b length_b	46.866 Å
Unit-cell length c length_c	123.987 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.72 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	4

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

Resolution resolution	1.800 Å
Low-resolution limit resolution_low	19.560 Å
R factor r_factor	0.2330
R_work r_work	0.2330
R_free r_free	0.2490

Hetero SAM domain structure of Ph and Scm.

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

Polyhomeotic-proximal chromatin protein

State in the Current Structure

Other States of the Same Protein in the Database

Sex comb on midleg CG9495-PA

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

1pk1__assembly_1__model_1

1pk1__assembly_1__model_1 | I(q)

1pk1__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 (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) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Hetero SAM domain structure of Ph and Scm.

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

Polyhomeotic-proximal chromatin protein

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Sex comb on midleg CG9495-PA

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

1pk1__assembly_1__model_1

1pk1__assembly_1__model_1 | I(q)

1pk1__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 (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) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)