SAXSdb — 1now

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

beta-hexosaminidase beta chain

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Homooligomer	Protein 2 其他Polymer 2	2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 (2R,3R,4S,5R)-2-ACETAMIDO-3,4-DIHYDROXY-5-HYDROXYMETHYL-PIPERIDINE × 2 GLYCEROL × 4 water × 2	Consistent with protein count
2	Other combination	Homooligomer	Protein 2 其他Polymer 2	2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 (2R,3R,4S,5R)-2-ACETAMIDO-3,4-DIHYDROXY-5-HYDROXYMETHYL-PIPERIDINE × 2 GLYCEROL × 2 SULFATE ION × 2 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HEXB_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–507； UniProt 50–556 Author chain B； PDBConstruct 1–507； UniProt 50–556

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	1now
Deposition date deposition_date	2003-01-16
Structure title title	Human lysosomal beta-hexosaminidase isoform B in complex with (2R,3R,4S,5R)-2-Acetamido-3,4-Dihydroxy-5-Hydroxymethyl-Piperidinium Chloride (GalNAc-isofagomine)
Keywords keywords	(Beta/alpha)8-barrel, homodimer, family 20 glycosidase, HYDROLASE; HYDROLASE
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.

1now__assembly_2__model_1

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

Download this curve (.dat)

1now__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1now__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	32.49 Å
Rg (electron density)	31.66 Å
Total Rg	32.48 Å
Atom count	7862
Residues	960
Excluded volume	140280 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1now__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1now__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 (6)

Entity 1 Entity 1 polymer

Description description	beta-hexosaminidase beta chain
Molecular weight formula_weight	58184.9 kDa
EC 编号 ec_number	3.2.1.52
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	8184

AKPGPALWPLPLSVKMTPNLLHLAPENFYISHSPNSTAGPSCTLLEEAFRRYHGYIFGFYKWHHEPAEFQAKTQVQQLLVSITLQSECDAFPNISSDESYTLLVKEPVAVLKANRVWGALRGLETFSQLVYQDSYGTFTINESTIIDSPRFSHRGILIDTSRHYLPVKIILKTLDAMAFNKFNVLHWHIVDDQSFPYQSITFPELSNKGSYSLSHVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKGQKDLLTPCYSRQNKLDSFGPINPTLNTTYSFLTTFFKEISEVFPDQFIHLGGDEVEFKCWESNPKIQDFMRQKGFGTDFKKLESFYIQKVLDIIATINKGSIVWQEVFDDKAKLAPGTIVEVWKDSAYPEELSRVTASGFPVILSAPWYLDLISYGQDWRKYYKVEPLDFGGTQKQKQLFIGGEACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDAYDRLTRHRCRMVERGIAAQPLYAGYCNHENM

Entity 2 Entity 2 branched

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	424.4 kDa
Source method src_method	man
Copy count entity_count	2

Entity 3 Entity 3 non-polymer

Description description	(2R,3R,4S,5R)-2-ACETAMIDO-3,4-DIHYDROXY-5-HYDROXYMETHYL-PIPERIDINE
Molecular weight formula_weight	204.2 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 4 Entity 4 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 5 Entity 5 non-polymer

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

Entity 6 Entity 6 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	321

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1nowa1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.1 — TIM beta/alpha-barrel
Superfamily Superfamily superfamily	c.1.8 — (Trans)glycosidases
Family Family family	c.1.8.6 — beta-N-acetylhexosaminidase catalytic domain

Domain ID domain_id	d1nowa2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.92 — Zincin-like
Superfamily Superfamily superfamily	d.92.2 — beta-N-acetylhexosaminidase-like domain
Family Family family	d.92.2.1 — beta-N-acetylhexosaminidase domain

Domain ID domain_id	d1nowb1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.1 — TIM beta/alpha-barrel
Superfamily Superfamily superfamily	c.1.8 — (Trans)glycosidases
Family Family family	c.1.8.6 — beta-N-acetylhexosaminidase catalytic domain

Domain ID domain_id	d1nowb2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.92 — Zincin-like
Superfamily Superfamily superfamily	d.92.2 — beta-N-acetylhexosaminidase-like domain
Family Family family	d.92.2.1 — beta-N-acetylhexosaminidase domain

CATH v4.4 (4 domains)

Domain ID domain_id	1nowA01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	379 — Chitobiase; domain 2
Homologous superfamily homologous superfamily	10 — Chitobiase/beta-hexosaminidase domain 2-like

Domain ID domain_id	1nowA02
Class class	3 — Alpha Beta
Architecture architecture	20 — Alpha-Beta Barrel
Topology topology	20 — TIM Barrel
Homologous superfamily homologous superfamily	80 — Glycosidases

Domain ID domain_id	1nowB01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	379 — Chitobiase; domain 2
Homologous superfamily homologous superfamily	10 — Chitobiase/beta-hexosaminidase domain 2-like

Domain ID domain_id	1nowB02
Class class	3 — Alpha Beta
Architecture architecture	20 — Alpha-Beta Barrel
Topology topology	20 — TIM Barrel
Homologous superfamily homologous superfamily	80 — Glycosidases

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Unit-cell length a length_a	112.391 Å
Unit-cell length b length_b	112.391 Å
Unit-cell length c length_c	397.309 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	24

Space group space_group	P 61 2 2
Space-group number int_tables_number	178
Crystal system crystal_system	—

Resolution resolution	2.200 Å
Low-resolution limit resolution_low	34.710 Å
R factor r_factor	0.1944
R_work r_work	0.1931
R_free r_free	0.2176

Human lysosomal beta-hexosaminidase isoform B in complex with (2R,3R,4S,5R)-2-Acetamido-3,4-Dihydroxy-5-Hydroxymethyl-Piperidinium Chloride (GalNAc-isofagomine)

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

beta-hexosaminidase beta chain

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

1now__assembly_2__model_1

1now__assembly_2__model_1 | I(q)

1now__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 (6)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 branched

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Human lysosomal beta-hexosaminidase isoform B in complex with (2R,3R,4S,5R)-2-Acetamido-3,4-Dihydroxy-5-Hydroxymethyl-Piperidinium Chloride (GalNAc-isofagomine)

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

beta-hexosaminidase beta chain

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

1now__assembly_2__model_1

1now__assembly_2__model_1 | I(q)

1now__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 (6)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 branched

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)