6kxs

Cryo-EM structure of human IgM-Fc in complex with the J chain and the ectodomain of pIgR

Method: ELECTRON MICROSCOPY

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

Immunoglobulin heavy constant mu

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 12 其他Polymer 1	Immunoglobulin J chain × 1 （P01591） Polymeric immunoglobulin receptor × 1 （P01833） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 10	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IGHM_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 36–383； UniProt 106–453 Author chain B； PDBConstruct 36–383； UniProt 106–453 Author chain C； PDBConstruct 36–383； UniProt 106–453 Author chain D； PDBConstruct 36–383； UniProt 106–453 Author chain E； PDBConstruct 36–383； UniProt 106–453 Author chain F； PDBConstruct 36–383； UniProt 106–453 Author chain G； PDBConstruct 36–383； UniProt 106–453 Author chain H； PDBConstruct 36–383； UniProt 106–453 Author chain K； PDBConstruct 36–383； UniProt 106–453 Author chain L； PDBConstruct 36–383； UniProt 106–453

Immunoglobulin J chain

Homo sapiens

UniProt P01591

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 12 其他Polymer 1	Immunoglobulin heavy constant mu × 10 （P01871） Polymeric immunoglobulin receptor × 1 （P01833） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 10	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IGJ_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain J； PDBConstruct 1–136； UniProt 24–159

Polymeric immunoglobulin receptor

Homo sapiens

UniProt P01833

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 12 其他Polymer 1	Immunoglobulin heavy constant mu × 10 （P01871） Immunoglobulin J chain × 1 （P01591） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 10	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	PIGR_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain P； PDBConstruct 1–547； UniProt 19–565

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	6kxs
Deposition date deposition_date	2019-09-12
Structure title title	Cryo-EM structure of human IgM-Fc in complex with the J chain and the ectodomain of pIgR
Keywords keywords	immunoglobulin, pentamer, transcytosis, secreted, IMMUNE SYSTEM; IMMUNE SYSTEM
Experimental Method method	ELECTRON MICROSCOPY

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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.

6kxs__assembly_1__model_1

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

Download this curve (.dat)

6kxs__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6kxs__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	57.26 Å
Rg (electron density)	57.14 Å
Total Rg	57.10 Å
Atom count	22499
Residues	2869
Excluded volume	398940 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6kxs__assembly_1__model_1`	dodecameric （12）	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 (5)

Entity 1 Entity 1 polymer

Description description	Immunoglobulin heavy constant mu
Molecular weight formula_weight	41875.8 kDa
Source method src_method	man
Copy count entity_count	10

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D,E,F,G,H,K,L
Atom count atom_count	22499

ASAWSHPQFEKGGGSGGGSGGSAWSHPQFEKIDTTIAELPPKVSVFVPPRDGFFGNPRKSKLICQATGFSPRQIQVSWLREGKQVGSGVTTDQVQAEAKESGPTTYKVTSTLTIKESDWLGQSMFTCRVDHRGLTFQQNASSMCVPDQDTAIRVFAIPPSFASIFLTKSTKLTCLVTDLTTYDSVTISWTRQNGEAVKTHTNISESHPNATFSAVGEASICEDDWNSGERFTCTVTHTDLPSPLKQTISRPKGVALHRPDVYLLPPAREQLNLRESATITCLVTGFSPADVFVQWMQRGQPLSPEKYVTSAPMPEPQAPGRYFAHSILTVSEEEWNTGETYTCVVAHEALPNRVTERTVDKSTGKPTLYNVSLVMSDTAGTCY

Source Source

Source organism organism	Homo sapiens
Common name common_name	Human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 2 Entity 2 polymer

Description description	Immunoglobulin J chain
Molecular weight formula_weight	15483.3 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	J

EDERIVLVDNKCKCARITSRIIRSSEDPNEDIVERNIRIIVPLNNRENISDPTSPLRTRFVYHLSDLCKKCDPTEVELDNQIVTATQSNICDEDSATETCYTYDRNKCYTAVVPLVYGGETKMVETALTPDACYPD

Source Source

Source organism organism	Homo sapiens
Common name common_name	Human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 3 Entity 3 polymer

Description description	Polymeric immunoglobulin receptor
Molecular weight formula_weight	61371.9 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	P

KSPIFGPEEVNSVEGNSVSITCYYPPTSVNRHTRKYWCRQGARGGCITLISSEGYVSSKYAGRANLTNFPENGTFVVNIAQLSQDDSGRYKCGLGINSRGLSFDVSLEVSQGPGLLNDTKVYTVDLGRTVTINCPFKTENAQKRKSLYKQIGLYPVLVIDSSGYVNPNYTGRIRLDIQGTGQLLFSVVINQLRLSDAGQYLCQAGDDSNSNKKNADLQVLKPEPELVYEDLRGSVTFHCALGPEVANVAKFLCRQSSGENCDVVVNTLGKRAPAFEGRILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLFVNEESTIPRSPTVVKGVAGGSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSEGWVKAQYEGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIEGEPNLKVPGNVTAVLGETLKVPCHFPCKFSSYEKYWCKWNNTGCQALPSQDEGPSKAFVNCDENSRLVSLTLNLVTRADEGWYWCGVKQGHFYGETAAVYVAVEERHHHHHHHH

Source Source

Source organism organism	Homo sapiens
Common name common_name	Human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 4 Entity 4 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	1

Entity 5 Entity 5 non-polymer

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	221.2 kDa
Source method src_method	man
Copy count entity_count	10

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6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

Domain ID domain_id	6kxsA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsC01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsC02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsD01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsD02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsE01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsE02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsF01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsF02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsG01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsG02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsH01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsH02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsK01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsK02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsL01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	6kxsL02
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	1.000 Å
Unit-cell length b length_b	1.000 Å
Unit-cell length c length_c	1.000 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	—

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

Resolution resolution	3.40 Å
Resolution测定Method resolution_method	—
颗粒数 num_particles	1183008

Cryo-EM structure of human IgM-Fc in complex with the J chain and the ectodomain of pIgR

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

Immunoglobulin heavy constant mu

State in the Current Structure

Other States of the Same Protein in the Database

Immunoglobulin J chain

State in the Current Structure

Other States of the Same Protein in the Database

Polymeric immunoglobulin receptor

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

6kxs__assembly_1__model_1

6kxs__assembly_1__model_1 | I(q)

6kxs__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

冷冻电镜 EM 3D

5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 branched

Entity 5 Entity 5 non-polymer

6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

7. Citations (1)

Cryo-EM structure of human IgM-Fc in complex with the J chain and the ectodomain of pIgR

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

Immunoglobulin heavy constant mu

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Immunoglobulin J 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

Polymeric immunoglobulin receptor

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

6kxs__assembly_1__model_1

6kxs__assembly_1__model_1 | I(q)

6kxs__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

冷冻电镜 EM 3D

5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 branched

Entity 5 Entity 5 non-polymer

6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

7. Citations (1)