33CI: MAGE-A4 (230-239)-bound HLA-A*02:01

Cryo-EM structure of MAGE-A4 (230-239)-bound HLA-A*02:01 in complex with Fab VR-58. Determined by electron microscopy at 2.2 Å resolution. Released 26 Aug 2026.

Method
Electron microscopy
Resolution
2.2 Å
Organisms
Homo sapiens, Mus musculus
Chains
7
Atoms
6,642
Mol. weight
146.79 kDa
Released
26 Aug 2026

Explore 33CI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

33CI contains 27 α-helices and 78 β-strands across 6 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 11 helices, 19 β-strands

ElementResiduesLengthSheet
β-strand3-12101
α-helix201
β-strand21-2881
β-strand31-3771
β-strand46-4721
α-helix50-523
α-helix57-8428
β-strand94-103101
β-strand109-118101
β-strand121-12661
β-strand133-13531
α-helix138-14912
α-helix152-1587
α-helix159-1635
α-helix164-17411
α-helix176-1794
β-strand18312
α-helix184-1852
β-strand186-19383
β-strand198-208113
β-strand20912
β-strand214-21964
β-strand222-22324
β-strand228-23033
α-helix231-2333
β-strand234-23523
β-strand241-250103
α-helix253-2564
β-strand257-26264
β-strand270-27344
Chain B: 3 helices, 11 β-strands
ElementResiduesLengthSheet
β-strand315
α-helix4-52
β-strand6-1166
β-strand21-30106
β-strand3115
β-strand36-4167
β-strand44-4527
α-helix461
β-strand50-5126
α-helix52-543
β-strand55-5626
β-strand62-7096
β-strand78-8367
β-strand91-9447
Chain D: 3 helices, 12 β-strands
ElementResiduesLengthSheet
β-strand5112
β-strand9-12413
β-strand18-23612
α-helix25-284
α-helix31-322
β-strand33-37513
β-strand44-47413
β-strand48114
β-strand52114
β-strand61-66612
β-strand69-74612
α-helix79-813
β-strand83-89713
β-strand99-100213
β-strand104-108513
Chain E: 2 helices, 13 β-strands
ElementResiduesLengthSheet
β-strand3-7515
β-strand11-12216
β-strand18-25815
β-strand34-39617
β-strand45-51717
β-strand57-59317
β-strand64115
β-strand67-72615
α-helix73-753
β-strand77-82615
α-helix87-893
β-strand91-98817
β-strand109-112417
β-strand116-118317
β-strand119-120216
Chain F: 4 helices, 11 β-strands
ElementResiduesLengthSheet
β-strand4-748
β-strand10-1349
β-strand19-2578
β-strand33-3869
β-strand44-4969
β-strand53-5429
α-helix551
β-strand62-6768
β-strand70-7568
α-helix80-823
β-strand85-9069
α-helix971
β-strand9819
α-helix991
β-strand102-10659
Chain G: 4 helices, 12 β-strands
ElementResiduesLengthSheet
β-strand3-6410
α-helix7-93
β-strand10-12311
β-strand18-25810
α-helix29-313
β-strand34-39611
β-strand45-52811
β-strand57-60411
α-helix62-643
β-strand65110
β-strand68-73610
β-strand78-83610
α-helix88-903
β-strand92-100911
β-strand105-109511
β-strand113-117511

Molecules and chains

MoleculeChainsTypeLengthOrganismUniProt
MHC class I antigenAprotein296Homo sapiensF6IQS1 (AlphaFold model)
Beta-2-microglobulinBprotein100Homo sapiensP61769 (AlphaFold model)
Melanoma-associated antigen 4Cprotein10Homo sapiensP43358 (AlphaFold model)
Fab BBM.1 light chainFprotein214Mus musculus
Fab BBM.1 heavy chainGprotein222Mus musculus
Fab VR-6 light chainDprotein215Homo sapiens
Fab VR-6 heavy chainEprotein277Homo sapiens
Sequence of entity 1 (A), FASTA
>33CI_1 MHC class I antigen (chains A)
MGSHSMRYFFTSVSRPGRGEPRFIAVGYVDDTQFVRFDSDAASQRMEPRAPWIEQEGPEY
WDGETRKVKAHSQTHRVDLGTLRGCYNQSEAGSHTVQRMYGCDVGSDWRFLRGYHQYAYD
GKDYIALKEDLRSWTAADMCAQTTKHKWEAAHVAEQLRAYLEGTCVEWLRRYLENGKETL
QRTDAPKTHMTHHAVSDHEATLRCWALSFYPAEITLTWQRDGEDQTQDTELVETRPAGDG
TFQKWAAVVVPSGQEQRYTCHVQHEGLPKPLTLRWEPGSGSGLNDIFEAQKIEWHE
Sequence of entity 2 (B), FASTA
>33CI_2 Beta-2-microglobulin (chains B)
MIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKD
WSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM
Sequence of entity 3 (C), FASTA
>33CI_3 Melanoma-associated antigen 4 (chains C)
GVYDGREHTV
Sequence of entity 4 (F), FASTA
>33CI_4 Fab BBM.1 light chain (chains F)
DIQMTQSPASQSASLGESVTITCLASQTIGTWLAWYQQKPGKSPQLLIYAATSLADGVPS
RFSGSGSGTKFSLKIRTLQAEDFVSYYCQQLYSKPYTFGGGTKLEIKRTVAAPSVFIFPP
SDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLT
LSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC
Sequence of entity 5 (G), FASTA
>33CI_5 Fab BBM.1 heavy chain (chains G)
EVQLQQSGAELVKPGASVKLSCTPSGFNVKDTYIHWVKQRPKQGLEWIGRIDPSDGDIKY
DPKFQGKATITADTSSNTVSLQLSSLTSEDTAVYYCARWFGDYGAMNYWGQGTSVTVSSA
STKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSG
LYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC
Sequence of entity 6 (D), FASTA
>33CI_6 Fab VR-6 light chain (chains D)
SYELTQPPSVSVSPGQTASITCTADTLSRSYASWYQQKPGQSPVLVIYRDTSRPSGIPER
FSGSNSGNTATLTISGTQAMDEADYYCATRPSSGSNFQLFGGGTKLTVLGQPKAAPSVTL
FPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGVETTTPSKQSNNKYAASSY
LSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS
Sequence of entity 7 (E), FASTA
>33CI_7 Fab VR-6 heavy chain (chains E)
ESQVLESGGGSVQPGGSLRLSCTVSGFSLSNYAMSWVRQAPGKGLEYIGIVSSGGTTYYA
SWAKGRFTISKDTSKNTVYLQMNSLRAEDTASYYCAKDLYYGPTTYSAFNLWGQGTSVTV
SSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQ
SSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCAAAEQKLISEEDLNE
MEQKLISEEDLNEMEQKLISEEDLNEMAAHHHHHHHH

Primary citation

Systematic De-Risking of TCR-Mimic Therapeutics Through Proteome-Wide Off-Target Landscaping and a Generalizable Design Rule Framework. Schuster, S., Hartl, F.A., Stehle, J. et al. To be published.

Other PDB entries of the same protein (UniProt F6IQS1 (AlphaFold model), which also has an AlphaFold model), best resolution first:

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