9rcv

Structure of the Human Peptide-Loading Complex Arrested by HCMV US6

Method: ELECTRON MICROSCOPY

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

Antigen peptide transporter 1

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Tapasin × 2 （O15533） MHC class I antigen × 2 （A0A678ZHF8） Beta-2-microglobulin × 2 （P61769） Antigen peptide transporter 2 × 1 （Q03519） Unique short US6 glycoprotein × 1 （P14334） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	TAP1_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–748； UniProt 1–748

Tapasin

OrganismNot specified

UniProt O15533

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Antigen peptide transporter 1 × 1 （Q03518） MHC class I antigen × 2 （A0A678ZHF8） Beta-2-microglobulin × 2 （P61769） Antigen peptide transporter 2 × 1 （Q03519） Unique short US6 glycoprotein × 1 （P14334） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	TPSN_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–448； UniProt 1–448 Author chain F； PDBConstruct 1–448； UniProt 1–448

MHC class I antigen

OrganismNot specified

UniProt A0A678ZHF8

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Antigen peptide transporter 1 × 1 （Q03518） Tapasin × 2 （O15533） Beta-2-microglobulin × 2 （P61769） Antigen peptide transporter 2 × 1 （Q03519） Unique short US6 glycoprotein × 1 （P14334） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	A0A678ZHF8_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–362； UniProt 1–362 Author chain G； PDBConstruct 1–362； UniProt 1–362

Beta-2-microglobulin

OrganismNot specified

UniProt P61769

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Antigen peptide transporter 1 × 1 （Q03518） Tapasin × 2 （O15533） MHC class I antigen × 2 （A0A678ZHF8） Antigen peptide transporter 2 × 1 （Q03519） Unique short US6 glycoprotein × 1 （P14334） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	B2MG_HUMAN
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain D； PDBConstruct 1–119； UniProt 1–119 Author chain H； PDBConstruct 1–119； UniProt 1–119

Antigen peptide transporter 2

OrganismNot specified

UniProt Q03519

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Antigen peptide transporter 1 × 1 （Q03518） Tapasin × 2 （O15533） MHC class I antigen × 2 （A0A678ZHF8） Beta-2-microglobulin × 2 （P61769） Unique short US6 glycoprotein × 1 （P14334） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	TAP2_HUMAN
Isoform	—
PDB entities	5
Chains and sequence ranges	Author chain E； PDBConstruct 1–677； UniProt 7–683

Unique short US6 glycoprotein

Homo sapiens

UniProt P14334

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 9 其他Polymer 2	Antigen peptide transporter 1 × 1 （Q03518） Tapasin × 2 （O15533） MHC class I antigen × 2 （A0A678ZHF8） Beta-2-microglobulin × 2 （P61769） Antigen peptide transporter 2 × 1 （Q03519） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-5'-TRIPHOSPHATE × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ADENOSINE-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	US06_HCMVA
Isoform	—
PDB entities	6
Chains and sequence ranges	Author chain I； PDBConstruct 1–183； UniProt 1–183

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	9rcv
Deposition date deposition_date	2025-05-29
Structure title title	Structure of the Human Peptide-Loading Complex Arrested by HCMV US6
Keywords keywords	;antigen processing, adaptive immunity, cryo-EM, ER chaperones, MHC class I, transporter associated with antigen processing, 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.

9rcv__assembly_1__model_1

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

Download this curve (.dat)

9rcv__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

9rcv__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	67.88 Å
Rg (electron density)	67.66 Å
Total Rg	67.49 Å
Atom count	23525
Residues	2993
Excluded volume	418550 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`9rcv__assembly_1__model_1`	nonameric （9）	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 (12)

Entity 1 Entity 1 polymer

Description description	Antigen peptide transporter 1
Molecular weight formula_weight	81080.4 kDa
EC 编号 ec_number	7.4.2.14
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	23529

MASSRCPAPRGCRCLPGASLAWLGTVLLLLADWVLLRTALPRIFSLLVPTALPLLRVWAVGLSRWAVLWLGACGVLRATVGSKSENAGAQGWLAALKPLAAALGLALPGLALFRELISWGAPGSADSTRLLHWGSHPTAFVVSYAAALPAAALWHKLGSLWVPGGQGGSGNPVRRLLGCLGSETRRLSLFLVLVVLSSLGEMAIPFFTGRLTDWILQDGSADTFTRNLTLMSILTIASAVLEFVGDGIYNNTMGHVHSHLQGEVFGAVLRQETEFFQQNQTGNIMSRVTEDTSTLSDSLSENLSLFLWYLVRGLCLLGIMLWGSVSLTMVTLITLPLLFLLPKKVGKWYQLLEVQVRESLAKSSQVAIEALSAMPTVRSFANEEGEAQKFREKLQEIKTLNQKEAVAYAVNSWTTSISCMLLKVGILYIGGQLVTSGAVSSGNLVTFVLYQMQFTQAVEVLLSIYPRVQKAVGSSEKIFEYLDRTPRCPPSGLLTPLHLEGLVQFQDVSFAYPNRPDVLVLQGLTFTLRPGEVTALVGPNGSGKSTVAALLQNLYQPTGGQLLLDGKPLPQYEHRYLHRQVAAVGQEPQVFGRSLQENIAYGLTQKPTMEEITAAAVKSGAHSFISGLPQGYDTEVDEAGSQLSGGQRQAVALARALIRKPCVLILDDATSALDANSQLQVEQLLYESPERYSRSVLLITQHLSLVEQADHILFLEGGAIREGGTHQQLMEKKGCYWAMVQAPADAPE

Entity 2 Entity 2 polymer

Description description	Tapasin
Molecular weight formula_weight	47673.5 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

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

MKSLSLLLAVALGLATAVSAGPAVIECWFVEDASGKGLAKRPGALLLRQGPGEPPPRPDLDPELYLSVHDPAGALQAAFRRYPRGAPAPHCEMSRFVPLPASAKWASGLTPAQNCPRALDGAWLMVSISSPVLSLSSLLRPQPEPQQEPVLITMATVVLTVLTHTPAPRVRLGQDALLDLSFAYMPPTSEAASSLAPGPPPFGLEWRRQHLGKGHLLLAATPGLNGQMPAAQEGAVAFAAWDDDEPWGPWTGNGTFWLPRVQPFQEGTYLATIHLPYLQGQVTLELAVYKPPKVSLMPATLARAAPGEAPPELLCLVSHFYPSGGLEVEWELRGGPGGRSQKAEGQRWLSALRHHSDGSVSLSGHLQPPPVTTEQHGARYACRIHHPSLPASGRSAEVTLEVAGLSGPSLEDSVGLFLSAFLLLGLFKALGWAAVYLSTCKDSKKKAE

Entity 3 Entity 3 polymer

Description description	MHC class I antigen
Molecular weight formula_weight	40481.0 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C,G

MLVMAPRTVLLLLSAALALTETWAGSHSMRYFYTSVSRPGRGEPRFISVGYVDDTQFVRFDSDAASPREEPRAPWIEQEGPEYWDRNTQIYKAQAQTDRESLRNLRGYYNQSEAGSHTLQSMYGCDVGPDGRLLRGHDQYAYDGKDYIALNEDLRSWTAADTAAQITQRKWEAAREAEQRRAYLEGECVEWLRRYLENGKDKLERADPPKTHVTHHPISDHEATLRCWALGFYPAEITLTWQRDGEDQTQDTELVETRPAGDRTFQKWAAVVVPSGEEQRYTCHVQHEGLPKPLTLRWEPSSQSTVPIVGIVAGLAVLAVVVIGAVVAAVMCRKKSSGGKGGSYSQAACSDSAQGSDVSLTA

Entity 4 Entity 4 polymer

Description description	Beta-2-microglobulin
Molecular weight formula_weight	13732.5 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

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

MSRSVALAVLALLSLSGLEAIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

Entity 5 Entity 5 polymer

Description description	Antigen peptide transporter 2
Molecular weight formula_weight	74697.2 kDa
EC 编号 ec_number	7.4.2.14
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	E

RPWTSLLLVDAALLWLLQGPLGTLLPQGLPGLWLEGTLRLGGLWGLLKLRGLLGFVGTLLLPLCLATPLTVSLRALVAGASRAPPARVASAPWSWLLVGYGAAGLSWSLWAVLSPPGAQEKEQDQVNNKVLMWRLLKLSRPDLPLLVAAFFFLVLAVLGETLIPHYSGRVIDILGGDFDPHAFASAIFFMCLFSFGSSLSAGCRGGCFTYTMSRINLRIREQLFSSLLRQDLGFFQETKTGELNSRLSSDTTLMSNWLPLNANVLLRSLVKVVGLYGFMLSISPRLTLLSLLHMPFTIAAEKVYNTRHQEVLREIQDAVARAGQVVREAVGGLQTVRSFGAEEHEVCRYKEALEQCRQLYWRRDLERALYLLVRRVLHLGVQMLMLSCGLQQMQDGELTQGSLLSFMIYQESVGSYVQTLVYIYGDMLSNVGAAEKVFSYMDRQPNLPSPGTLAPTTLQGVVKFQDVSFAYPNRPDRPVLKGLTFTLRPGEVTALVGPNGSGKSTVAALLQNLYQPTGGQVLLDEKPISQYEHCYLHSQVVSVGQEPVLFSGSVRNNIAYGLQSCEDDKVMAAAQAAHADDFIQEMEHGIYTDVGEKGSQLAAGQKQRLAIARALVRDPRVLILDEATSALDVQCEQALQDWNSRGDRTVLVIAHRLQTVQRAHQILVLQEGKLQKL

Entity 6 Entity 6 polymer

Description description	Unique short US6 glycoprotein
Molecular weight formula_weight	20671.1 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	I

MDLLIRLGFLLMCALPTPGERSSRDPKTLLSLSPRQQACVPRTKSHRPVCYNDTGDCTDADDSWKQLGEDFAHQCLQAAKKRPKTHKSRPNDRNLEGRLTCQRVRRLLPCDLDIHPSHRLLTLMNNCVCDGAVWNAFRLIERHGFFAVTLYLCCGITLLVVILALLCSITYESTGRGIRRCGS

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 7 Entity 7 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 8 Entity 8 non-polymer

Description description	ADENOSINE-5'-TRIPHOSPHATE
Molecular weight formula_weight	507.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 9 Entity 9 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 10 Entity 10 non-polymer

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

Entity 11 Entity 11 non-polymer

Description description	ADENOSINE-5'-DIPHOSPHATE
Molecular weight formula_weight	427.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 12 Entity 12 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	4

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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	triclinic

Resolution resolution	2.70 Å
Resolution测定Method resolution_method	—
颗粒数 num_particles	269213

Structure of the Human Peptide-Loading Complex Arrested by HCMV US6

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

Antigen peptide transporter 1

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Tapasin

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

MHC class I antigen

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-2-microglobulin

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Antigen peptide transporter 2

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Unique short US6 glycoprotein

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

9rcv__assembly_1__model_1

9rcv__assembly_1__model_1 | I(q)

9rcv__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 (12)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 polymer

Polymer Polymer

Entity 5 Entity 5 polymer

Polymer Polymer

Entity 6 Entity 6 polymer

Polymer Polymer

Source Source

Entity 7 Entity 7 branched

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 non-polymer

Entity 10 Entity 10 non-polymer

Entity 11 Entity 11 non-polymer

Entity 12 Entity 12 water

7. Citations (2)