SAXSdb — 3sqc

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

SQUALENE--HOPENE CYCLASE

Alicyclobacillus acidocaldarius

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 monomer	Monomer	Protein 1	water × 1	Consistent with protein count
3	Protein monomer	Monomer	Protein 1	water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SQHC_ALIAC
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 2–631； UniProt 1–630 Author chain B； PDBConstruct 2–631； UniProt 1–630 Author chain C； PDBConstruct 2–631； UniProt 1–630

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	3sqc
Deposition date deposition_date	1998-09-04
Structure title title	SQUALENE-HOPENE CYCLASE
Keywords keywords	TRITERPENE CYCLASE, MONOTOPIC MEMBRANE PROTEIN, QW-SEQUENCE REPEAT, CHOLESTEROL BIOSYNTHESIS, ISOMERASE; ISOMERASE
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.

3sqc__assembly_2__model_1

Assembly 2 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

3sqc__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3sqc__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	25.78 Å
Rg (electron density)	24.62 Å
Total Rg	25.64 Å
Atom count	4961
Residues	619
Excluded volume	87861 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3sqc__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3sqc__assembly_2__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`3sqc__assembly_3__model_1`	monomeric （1）	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)

Entity 1 Entity 1 polymer

Description description	SQUALENE--HOPENE CYCLASE
Molecular weight formula_weight	71638.1 kDa
EC 编号 ec_number	5.4.99.-
Mutation mutation	D376C
Source method src_method	man
Copy count entity_count	3

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C
Atom count atom_count	14997

MAEQLVEAPAYARTLDRAVEYLLSCQKDEGYWWGPLLSNVTMEAEYVLLCHILDRVDRDRMEKIRRYLLHEQREDGTWALYPGGPPDLDTTIEAYVALKYIGMSRDEEPMQKALRFIQSQGGIESSRVFTRMWLALVGEYPWEKVPMVPPEIMFLGKRMPLNIYEFGSWARATVVALSIVMSRQPVFPLPERARVPELYETDVPPRRRGAKGGGGWIFDALDRALHGYQKLSVHPFRRAAEIRALDWLLERQAGDGSWGGIQPPWFYALIALKILDMTQHPAFIKGWEGLELYGVELDYGGWMFQASISPVWDTGLAVLALRAAGLPADHDRLVKAGEWLLDRQITVPGDWAVKRPNLKPGGFAFQFDNVYYPDVCDTAVVVWALNTLRLPDERRRRDAMTKGFRWIVGMQSSNGGWGAYDVDNTSDLPNHIPFCDFGEVTDPPSEDVTAHVLECFGSFGYDDAWKVIRRAVEYLKREQKPDGSWFGRWGVNYLYGTGAVVSALKAVGIDTREPYIQKALDWVEQHQNPDGGWGEDCRSYEDPAYAGKGASTPSQTAWALMALIAGGRAESEAARRGVQYLVETQRPDGGWDEPYYTGTGFPGDFYLGYTMYRHVFPTLALGRYKQAIERR

Source Source

Source organism organism	Alicyclobacillus acidocaldarius
NCBI taxonomy ID ncbi_taxonomy_id	405212
Host organism host_organism	Escherichia coli K12

Entity 2 Entity 2 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	114

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6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d3sqca1
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

Domain ID domain_id	d3sqca2
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

Domain ID domain_id	d3sqcb1
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

Domain ID domain_id	d3sqcb2
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

Domain ID domain_id	d3sqcc1
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

Domain ID domain_id	d3sqcc2
Class class	a — All alpha proteins
Fold Fold fold	a.102 — alpha/alpha toroid
Superfamily Superfamily superfamily	a.102.4 — Terpenoid cyclases/Protein prenyltransferases
Family Family family	a.102.4.2 — Terpene synthases

CATH v4.4 (6 domains)

Domain ID domain_id	3sqcA01
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	3sqcA02
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	3sqcB01
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	3sqcB02
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	3sqcC01
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	3sqcC02
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

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Unit-cell length a length_a	140.960 Å
Unit-cell length b length_b	140.960 Å
Unit-cell length c length_c	243.800 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	18

Space group space_group	P 32 2 1
Space-group number int_tables_number	154
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	0.2090
R_work r_work	0.2090
R_free r_free	0.2360

SQUALENE-HOPENE CYCLASE

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

SQUALENE--HOPENE CYCLASE

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

3sqc__assembly_2__model_1

3sqc__assembly_2__model_1 | I(q)

3sqc__assembly_2__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (3)

SQUALENE-HOPENE CYCLASE

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

SQUALENE--HOPENE CYCLASE

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

3sqc__assembly_2__model_1

3sqc__assembly_2__model_1 | I(q)

3sqc__assembly_2__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (3)