1o23

CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE

Method: X-RAY DIFFRACTION

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

ALPHA-LACTALBUMIN

Mus musculus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	BETA-1,4-GALACTOSYLTRANSFERASE × 1 （P08037） CALCIUM ION × 1 TETRAETHYLENE GLYCOL × 1 2-(N-MORPHOLINO)-ETHANESULFONIC ACID × 1 MANGANESE (II) ION × 1 URIDINE-5'-DIPHOSPHATE-GLUCOSE × 1 URIDINE-5'-DIPHOSPHATE × 1 water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	BETA-1,4-GALACTOSYLTRANSFERASE × 1 （P08037） CALCIUM ION × 1 TETRAETHYLENE GLYCOL × 1 MANGANESE (II) ION × 1 URIDINE-5'-DIPHOSPHATE-GLUCOSE × 1 URIDINE-5'-DIPHOSPHATE × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	LALBA_MOUSE
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–123； UniProt 21–143 Author chain C； PDBConstruct 1–123； UniProt 21–143

BETA-1,4-GALACTOSYLTRANSFERASE

Bos taurus

UniProt P08037

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	ALPHA-LACTALBUMIN × 1 （P29752） CALCIUM ION × 1 TETRAETHYLENE GLYCOL × 1 2-(N-MORPHOLINO)-ETHANESULFONIC ACID × 1 MANGANESE (II) ION × 1 URIDINE-5'-DIPHOSPHATE-GLUCOSE × 1 URIDINE-5'-DIPHOSPHATE × 1 water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	ALPHA-LACTALBUMIN × 1 （P29752） CALCIUM ION × 1 TETRAETHYLENE GLYCOL × 1 MANGANESE (II) ION × 1 URIDINE-5'-DIPHOSPHATE-GLUCOSE × 1 URIDINE-5'-DIPHOSPHATE × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	B4GT1_BOVIN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–286； UniProt 130–402 Author chain D； PDBConstruct 1–286； UniProt 130–402

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	1o23
Deposition date deposition_date	2003-01-29
Structure title title	CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE
Keywords keywords	ALPHA-LACTALBUMIN; BETA, 1, 4-GALACTOSYLTRANSFERASE; UDP-GLUCOSE, TRANSFERASE ACTIVATOR-TRANSFERASE COMPLEX; TRANSFERASE ACTIVATOR/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.

1o23__assembly_1__model_1

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

Download this curve (.dat)

1o23__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1o23__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	22.82 Å
Rg (electron density)	22.17 Å
Total Rg	23.09 Å
Atom count	3286
Residues	395
Excluded volume	58465 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1o23__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1o23__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 (9)

Entity 1 Entity 1 polymer

Description description	ALPHA-LACTALBUMIN
Molecular weight formula_weight	14015.8 kDa
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	6972

TELTKCKVSHAIKDIDGYQGISLLEWACVLFHTSGYDTQAVVNDNGSTEYGLFQISDRFWCKSSEFPESENICGISCDKLLDDELDDDIACAKKILAIKGIDYWKAYKPMCSEKLEQWRCEKP

Source Source

Source organism organism	Mus musculus
Common name common_name	house mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Escherichia coli BL21

Entity 2 Entity 2 polymer

Description description	BETA-1,4-GALACTOSYLTRANSFERASE
Molecular weight formula_weight	32851.6 kDa
EC 编号 ec_number	2.4.1.90
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

ASMTGGQQMGRGSSLTACPEESPLLVGPMLIEFNIPVDLKLVEQQNPKVKLGGRYTPMDCISPHKVAIIIPFRNRQEHLKYWLYYLHPILQRQQLDYGIYVINQAGESMFNRAKLLNVGFKEALKDYDYNCFVFSDVDLIPMNDHNTYRCFSQPRHISVAMDKFGFSLPYVQYFGGVSALSKQQFLSINGFPNNYWGWGGEDDDIYNRLAFRGMSVSRPNAVIGKCRMIRHSRDKKNEPNPQRFDRIAHTKETMLSDGLNSLTYMVLEVQRYPLYTKITVDIGTPS

Source Source

Source organism organism	Bos taurus
Common name common_name	cattle
NCBI taxonomy ID ncbi_taxonomy_id	9913
Host organism host_organism	Escherichia coli BL21

Entity 3 Entity 3 non-polymer

Description description	CALCIUM ION
Molecular weight formula_weight	40.1 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 4 Entity 4 non-polymer

Description description	TETRAETHYLENE GLYCOL
Molecular weight formula_weight	194.2 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 5 Entity 5 non-polymer

Description description	2-(N-MORPHOLINO)-ETHANESULFONIC ACID
Molecular weight formula_weight	195.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 6 Entity 6 non-polymer

Description description	MANGANESE (II) ION
Molecular weight formula_weight	54.9 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 7 Entity 7 non-polymer

Description description	URIDINE-5'-DIPHOSPHATE-GLUCOSE
Molecular weight formula_weight	566.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 8 Entity 8 non-polymer

Description description	URIDINE-5'-DIPHOSPHATE
Molecular weight formula_weight	404.2 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 9 Entity 9 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	412

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1o23a_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.2 — Lysozyme-like
Superfamily Superfamily superfamily	d.2.1 — Lysozyme-like
Family Family family	d.2.1.2 — C-type lysozyme

Domain ID domain_id	d1o23b_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.68 — Nucleotide-diphospho-sugar transferases
Superfamily Superfamily superfamily	c.68.1 — Nucleotide-diphospho-sugar transferases
Family Family family	c.68.1.2 — beta 1,4 galactosyltransferase (b4GalT1)

Domain ID domain_id	d1o23c_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.2 — Lysozyme-like
Superfamily Superfamily superfamily	d.2.1 — Lysozyme-like
Family Family family	d.2.1.2 — C-type lysozyme

Domain ID domain_id	d1o23d_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.68 — Nucleotide-diphospho-sugar transferases
Superfamily Superfamily superfamily	c.68.1 — Nucleotide-diphospho-sugar transferases
Family Family family	c.68.1.2 — beta 1,4 galactosyltransferase (b4GalT1)

CATH v4.4 (4 domains)

Domain ID domain_id	1o23A00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	530 — Lysozyme
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	1o23B00
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	550 — Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A
Homologous superfamily homologous superfamily	10 — Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A

Domain ID domain_id	1o23C00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	530 — Lysozyme
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	1o23D00
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	550 — Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A
Homologous superfamily homologous superfamily	10 — Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A

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Unit-cell length a length_a	55.545 Å
Unit-cell length b length_b	99.379 Å
Unit-cell length c length_c	102.568 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	104.09 °
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	2.320 Å
Low-resolution limit resolution_low	19.960 Å
R factor r_factor	0.2010
R_work r_work	0.2010
R_free r_free	0.2650

CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE

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

ALPHA-LACTALBUMIN

State in the Current Structure

Other States of the Same Protein in the Database

BETA-1,4-GALACTOSYLTRANSFERASE

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

1o23__assembly_1__model_1

1o23__assembly_1__model_1 | I(q)

1o23__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 (9)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE

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

ALPHA-LACTALBUMIN

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

BETA-1,4-GALACTOSYLTRANSFERASE

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

1o23__assembly_1__model_1

1o23__assembly_1__model_1 | I(q)

1o23__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 (9)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)