SAXSdb — 2q3b

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

Cysteine synthase A

Mycobacterium tuberculosis

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	CHLORIDE ION × 2 (4S)-2-METHYL-2,4-PENTANEDIOL × 8 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CYSK_MYCTU
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 4–313； UniProt 1–310

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	2q3b
Deposition date deposition_date	2007-05-30
Structure title title	1.8 A Resolution Crystal Structure of O-Acetylserine Sulfhydrylase (OASS) Holoenzyme From MYCOBACTERIUM TUBERCULOSIS
Keywords keywords	;Mycobacterium tuberculosis, Pyridoxal-5'-phosphate, sulphur metabolism, cysteine biosynthesis, TRANSFERASE ;; TRANSFERASE
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.

2q3b__assembly_1__model_1

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

Download this curve (.dat)

2q3b__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2q3b__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	25.27 Å
Rg (electron density)	24.18 Å
Total Rg	25.02 Å
Atom count	4550
Residues	598
Excluded volume	81787 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2q3b__assembly_1__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	Cysteine synthase A
Molecular weight formula_weight	33296.0 kDa
EC 编号 ec_number	2.5.1.47
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	2527

GSHMSIAEDITQLIGRTPLVRLRRVTDGAVADIVAKLEFFNPANSVKDRIGVAMLQAAEQAGLIKPDTIILEPTSGNTGIALAMVCAARGYRCVLTMPETMSLERRMLLRAYGAELILTPGADGMSGAIAKAEELAKTDQRYFVPQQFENPANPAIHRVTTAEEVWRDTDGKVDIVVAGVGTGGTITGVAQVIKERKPSARFVAVEPAASPVLSGGQKGPHPIQGIGAGFVPPVLDQDLVDEIITVGNEDALNVARRLAREEGLLVGISSGAATVAALQVARRPENAGKLIVVVLPDFGERYLSTPLFADVAD

Source Source

Source organism organism	Mycobacterium tuberculosis
NCBI taxonomy ID ncbi_taxonomy_id	1773
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 2 Entity 2 non-polymer

Description description	CHLORIDE ION
Molecular weight formula_weight	35.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 3 Entity 3 non-polymer

Description description	(4S)-2-METHYL-2,4-PENTANEDIOL
Molecular weight formula_weight	118.2 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	203

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6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d2q3ba_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.79 — Tryptophan synthase beta subunit-like PLP-dependent enzymes
Superfamily Superfamily superfamily	c.79.1 — Tryptophan synthase beta subunit-like PLP-dependent enzymes
Family Family family	c.79.1.0 — automated matches

CATH v4.4 (2 domains)

Domain ID domain_id	2q3bA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1100 —

Domain ID domain_id	2q3bA02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1100 —

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Unit-cell length a length_a	70.991 Å
Unit-cell length b length_b	70.991 Å
Unit-cell length c length_c	179.624 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	8

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

Resolution resolution	1.800 Å
Low-resolution limit resolution_low	37.960 Å
R factor r_factor	0.1751
R_work r_work	0.1741
R_free r_free	0.1925

1.8 A Resolution Crystal Structure of O-Acetylserine Sulfhydrylase (OASS) Holoenzyme From MYCOBACTERIUM TUBERCULOSIS

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

Cysteine synthase A

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

2q3b__assembly_1__model_1

2q3b__assembly_1__model_1 | I(q)

2q3b__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 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

CATH v4.4 (2 domains)

7. Citations (1)

1.8 A Resolution Crystal Structure of O-Acetylserine Sulfhydrylase (OASS) Holoenzyme From MYCOBACTERIUM TUBERCULOSIS

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

Cysteine synthase A

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

2q3b__assembly_1__model_1

2q3b__assembly_1__model_1 | I(q)

2q3b__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 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 3 domains

SCOP 2.08 (1 domains)

CATH v4.4 (2 domains)

7. Citations (1)