SAXSdb — 6tqu

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

Motile sperm domain-containing protein 2

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	StAR-related lipid transfer protein 3 × 1 （Q14849） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	StAR-related lipid transfer protein 3 × 1 （Q14849） SULFATE ION × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	MSPD2_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 5–135； UniProt 315–445 Author chain B； PDBConstruct 5–135； UniProt 315–445

StAR-related lipid transfer protein 3

OrganismNot specified

UniProt Q14849

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	Motile sperm domain-containing protein 2 × 1 （Q8NHP6） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	Motile sperm domain-containing protein 2 × 1 （Q8NHP6） SULFATE ION × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	STAR3_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain C； PDBConstruct 1–21； UniProt 196–216 Author chain D； PDBConstruct 1–21； UniProt 196–216

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	6tqu
Deposition date deposition_date	2019-12-17
Structure title title	The crystal structure of the MSP domain of human MOSPD2 in complex with the Phospho-FFAT motif of STARD3.
Keywords keywords	Membrane contact sites, FFAT motif, MSP domain, Endoplasmic reticulum, PROTEIN BINDING; PROTEIN BINDING
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.

6tqu__assembly_1__model_1

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

Download this curve (.dat)

6tqu__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6tqu__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	16.04 Å
Rg (electron density)	14.72 Å
Total Rg	15.83 Å
Atom count	1037
Residues	132
Excluded volume	18437 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6tqu__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`6tqu__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 (4)

Entity 1 Entity 1 polymer

Description description	Motile sperm domain-containing protein 2
Molecular weight formula_weight	14833.1 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	2212

GSHMAFKKPLSVFKGPLLHISPAEELYFGSTESGEKKTLIVLTNVTKNIVAFKVRTTAPEKYRVKPSNSSCDPGASVDIVVSPHGGLTVSAQDRFLIMAAEMEQSSGTGPAELTQFWKEVPRNKVMEHRLRCHTV

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 BL21(DE3)

Entity 2 Entity 2 polymer

Description description	StAR-related lipid transfer protein 3
Molecular weight formula_weight	2434.3 kDa
Source method src_method	syn
Copy count entity_count	2

Polymer Polymer

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

CLFSGALSEGQFYSPPESFAG

Entity 3 Entity 3 non-polymer

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	89

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6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

Domain ID domain_id	6tquA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6tquB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

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Unit-cell length a length_a	87.968 Å
Unit-cell length b length_b	87.968 Å
Unit-cell length c length_c	95.130 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	16

Space group space_group	P 41 21 2
Space-group number int_tables_number	92
Crystal system crystal_system	—

Resolution resolution	2.400 Å
Low-resolution limit resolution_low	43.980 Å
R factor r_factor	0.1861
R_work r_work	0.1832
R_free r_free	0.2400

The crystal structure of the MSP domain of human MOSPD2 in complex with the Phospho-FFAT motif of STARD3.

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

Motile sperm domain-containing protein 2

State in the Current Structure

Other States of the Same Protein in the Database

StAR-related lipid transfer protein 3

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

6tqu__assembly_1__model_1

6tqu__assembly_1__model_1 | I(q)

6tqu__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

7. Citations (1)

The crystal structure of the MSP domain of human MOSPD2 in complex with the Phospho-FFAT motif of STARD3.

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

Motile sperm domain-containing protein 2

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

StAR-related lipid transfer protein 3

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

6tqu__assembly_1__model_1

6tqu__assembly_1__model_1 | I(q)

6tqu__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

7. Citations (1)