9IY6: BTN2A1-BTN3A1-BTN3A2 oligomer complex

BTN2A1-BTN3A1-BTN3A2 oligomer complex. Determined by electron microscopy at 10.0 Å resolution. Released 18 Feb 2026.

Method: Electron microscopy
Resolution: 10.0 Å
Organism: Homo sapiens
Chains: 8
Atoms: 13,310
Mol. weight: 437.29 kDa
Released: 18 Feb 2026

Explore 9IY6 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9IY6 contains 14 α-helices and 166 β-strands across 8 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 E: 1 helix, 24 β-strands

Element	Residues	Length	Sheet
β-strand	31-33	3	1
β-strand	41	1	2
β-strand	51	1	3
β-strand	52-54	3	1
β-strand	66	1	4
β-strand	77-79	3	5
β-strand	82-84	3	5
β-strand	97-98	2	6
α-helix	101-103	3
β-strand	108	1	3
β-strand	110-111	2	6
β-strand	122-123	2	7
β-strand	125	1	4
β-strand	126-129	4	8
β-strand	132-135	4	8
β-strand	138-139	2	7
β-strand	142	1	2
β-strand	152-157	6	9
β-strand	160-164	5	9
β-strand	188-191	4	10
β-strand	194-195	2	11
β-strand	201-202	2	11
β-strand	205-207	3	10
β-strand	220-221	2	12
β-strand	230-231	2	12

Chain F: 1 helix, 18 β-strands

Element	Residues	Length	Sheet
β-strand	41	1	13
β-strand	48-51	4	14
β-strand	78	1	15
β-strand	83	1	15
β-strand	97-98	2	14
α-helix	102-104	3
β-strand	108-111	4	14
β-strand	142	1	13
β-strand	144	1	16
β-strand	149-153	5	17
β-strand	161	1	18
β-strand	163-170	8	17
β-strand	171	1	16
β-strand	175-179	5	19
β-strand	195	1	17
β-strand	201-206	6	17
β-strand	209	1	18
β-strand	218-222	5	19
β-strand	230	1	19

Chain G: 2 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	46-49	4	20
β-strand	78-80	3	21
β-strand	83-85	3	21
α-helix	91-93	3
β-strand	97-100	4	20
β-strand	110-116	7	20
β-strand	145	1	22
β-strand	162-169	8	23
β-strand	172	1	22
β-strand	175-180	6	24
β-strand	189	1	24
α-helix	191-193	3
β-strand	203-210	8	23
β-strand	217-224	8	24
β-strand	229-236	8	24

Chain H: 2 helices, 15 β-strands

Element	Residues	Length	Sheet
β-strand	32-34	3	25
β-strand	48-55	8	25
α-helix	60-62	3
β-strand	64-68	5	26
β-strand	97-99	3	25
β-strand	103	1	25
β-strand	108-113	6	25
β-strand	125-129	5	26
β-strand	145	1	27
β-strand	162-171	10	28
β-strand	172	1	27
β-strand	175-178	4	29
β-strand	188	1	29
β-strand	202-210	9	28
β-strand	219-224	6	29
β-strand	230-234	5	29
α-helix	239-242	4

Chain I: 1 helix, 30 β-strands

Element	Residues	Length	Sheet
β-strand	31-33	3	30
β-strand	39-41	3	31
β-strand	45-48	4	32
β-strand	51	1	33
β-strand	52-54	3	30
β-strand	63-67	5	31
β-strand	76	1	31
β-strand	78-79	2	34
β-strand	82-83	2	34
β-strand	96-97	2	32
α-helix	102-104	3
β-strand	108	1	33
β-strand	111-115	5	32
β-strand	121-129	9	31
β-strand	132-142	11	31
β-strand	144	1	35
β-strand	150	1	36
β-strand	153-157	5	37
β-strand	160-163	4	37
β-strand	165	1	38
β-strand	166	1	36
β-strand	171	1	35
β-strand	175-177	3	39
β-strand	192-195	4	40
β-strand	201-204	4	40
β-strand	205	1	38
β-strand	208	1	37
β-strand	216	1	41
β-strand	220-222	3	39
β-strand	230-231	2	39
β-strand	235	1	41

Chain J: 2 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	48-50	3	42
β-strand	64-66	3	43
β-strand	76-78	3	43
β-strand	96-98	3	42
β-strand	109-112	4	42
α-helix	117-119	3
β-strand	124	1	44
β-strand	137	1	44
β-strand	152	1	45
β-strand	154	1	41
β-strand	161-162	2	46
β-strand	164	1	45
β-strand	167-170	4	47
β-strand	174	1	48
β-strand	178-179	2	49
α-helix	186-188	3
β-strand	194-195	2	47
β-strand	201-203	3	47
β-strand	208-209	2	46
β-strand	216-217	2	50
β-strand	218-219	2	49
β-strand	220-221	2	51
β-strand	223	1	48
β-strand	230-231	2	51
β-strand	234-235	2	50

Chain K: 3 helices, 22 β-strands

Element	Residues	Length	Sheet
β-strand	41-42	2	52
β-strand	49-50	2	53
β-strand	71	1	54
α-helix	91-93	3
β-strand	97-100	4	53
α-helix	104-106	3
β-strand	110-113	4	53
β-strand	123	1	54
β-strand	124	1	55
β-strand	139	1	55
β-strand	142-143	2	52
β-strand	145	1	56
β-strand	148	1	57
β-strand	162-168	7	58
β-strand	169	1	57
β-strand	172	1	56
β-strand	178	1	59
β-strand	180	1	60
β-strand	186	1	60
α-helix	192-194	3
β-strand	204-210	7	58
β-strand	217-218	2	61
β-strand	221-224	4	59
β-strand	229-232	4	59
β-strand	235-236	2	61

Chain L: 2 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	33-34	2	62
β-strand	39-43	5	63
β-strand	46-52	7	64
β-strand	53-54	2	62
β-strand	67-69	3	63
β-strand	74-79	6	63
β-strand	84-89	6	63
β-strand	97	1	64
β-strand	103	1	65
β-strand	108	1	65
β-strand	109-116	8	64
α-helix	118-120	3
β-strand	123-125	3	63
β-strand	139-144	6	63
β-strand	164-171	8	66
β-strand	178	1	67
α-helix	187-189	3
β-strand	196-197	2	66
β-strand	201-208	8	66
β-strand	216	1	68
β-strand	220-224	5	67
β-strand	229-233	5	67
β-strand	236	1	68

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Butyrophilin subfamily 2 member A1	E, F, I, J	protein	534	Homo sapiens	Q7KYR7 (AlphaFold model)
Butyrophilin subfamily 3 member A2	G, K	protein	340	Homo sapiens	P78410 (AlphaFold model)
Butyrophilin subfamily 3 member A1	H, L	protein	539	Homo sapiens	O00481 (AlphaFold model)

Sequence of entity 1 (E, F, I, J), FASTA

>9IY6_1 Butyrophilin subfamily 2 member A1 (chains E, F, I, J)
MDMRVPAQLLGLLLLWLSGARCQFIVVGPTDPILATVGENTTLRCHLSPEKNAEDMEVRW
FRSQFSPAVFVYKGGRERTEEQMEEYRGRTTFVSKDISRGSVALVIHNITAQENGTYRCY
FQEGRSYDEAILHLVVAGLGSKPLISMRGHEDGGIRLECISRGWYPKPLTVWRDPYGGVA
PALKEVSMPDADGLFMVTTAVIIRDKSVRNMSCSINNTLLGQKKESVIFIPESFMPSVSP
CAVALPIIVVILMIPIAVCIYWINKLQKEKKILSGEKEFERETREIALKELEKERVQKEE
ELQVKEKLQEELRWRRTFLHAVDVVLDPDTAHPDLFLSEDRRSVRRCPFRHLGESVPDNP
ERFDSQPCVLGRESFASGKHYWEVEVENVIEWTVGVCRDSVERKGEVLLIPQNGFWTLEM
HKGQYRAVSSPDRILPLKESLCRVGVFLDYEAGDVSFYNMRDRSHIYTCPRSAFSVPVRP
FFRLGCEDSPIFICPALTGANGVTVPEEGLTLHRVGTHQSLGSSGMDYKDDDDK

Sequence of entity 2 (G, K), FASTA

>9IY6_2 Butyrophilin subfamily 3 member A2 (chains G, K)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSNLHVEVKGYEDGGIHLECRSTGWYPQPQIQWSNAKGENI
PAVEAPVVADGVGLYEVAASVIMRGGSGEGVSCIIRNSLLGLEKTASISIADPFFRSAQP
WIAALAGTLPILLLLLAGASYFLWRQQKEITALSSEIESEQEMKEMGYAATEREISLRES
LQEELKRKKIQYLTRGEESSSDTNKSAGSSGMDYKDDDDK

Sequence of entity 3 (H, L), FASTA

>9IY6_3 Butyrophilin subfamily 3 member A1 (chains H, L)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSDLHVDVKGYKDGGIHLECRSTGWYPQPQIQWSNNKGENI
PTVEAPVVADGVGLYAVAASVIMRGSSGEGVSCTIRSSLLGLEKTASISIADPFFRSAQR
WIAALAGTLPVLLLLLGGAGYFLWQQQEEKKTQFRKKKREQELREMAWSTMKQEQSTRVK
LLEELRWRSIQYASRGERHSAYNEWKKALFKPADVILDPKTANPILLVSEDQRSVQRAKE
PQDLPDNPERFNWHYCVLGCESFISGRHYWEVEVGDRKEWHIGVCSKNVQRKGWVKMTPE
NGFWTMGLTDGNKYRTLTEPRTNLKLPKPPKKVGVFLDYETGDISFYNAVDGSHIHTFLD
VSFSEALYPVFRILTLEPTALTICPAGSSGAWSHPQFEKGGGSGGGSGGSAWSHPQFEK

Primary citation

Phosphoantigen-driven dissociation of butyrophilin oligomers activates gamma delta T cells. Xin, W., Huang, B., Gao, W. et al. Cell Discov (2026) 12. DOI 10.1038/s41421-026-00911-7 · PubMed

Other PDB entries of the same protein (UniProt Q7KYR7 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8IGT 1.56 Å, Crystal Structure of Intracellular B30.2 Domain of BTN2A1
8DFW 2.1 Å, Crystal Structure of Human BTN2A1 in Complex With Vgamma9-Vdelta2 T Cell Receptor
8JYE 2.18 Å, Crystal Structure of Intracellular B30.2 Domain of BTN3A1 and BTN2A1 in Complex with HMBPP
8JYC 2.29 Å, Crystal Structure of Intracellular B30.2 Domain of BTN3A1 and BTN2A1 in Complex with DMAPP
8VC7 2.76 Å, Crystal Structure of Human BTN2A1 ectodomain in complex with Antagonist 2A1.9 Fab
8ZHR 3.0 Å, Cryo-EM structure of the full-length pAg-bound BTN2A1-BTN3A1-BTN3A2 complex
9JQR 3.0 Å, Cryo-EM structure of the Vgamma9Vdelta2 TCR-engaged BTN3A1-BTN3A2-BTN2A1 complex
9IRD 3.2 Å, Cryo-EM structure of BTN2A1-BTN3A1-BTN3A2 mutant (BTN3A1 H381R, BTN2A1 R477A/T510A) in…
9JQQ 3.26 Å, Cryo-EM structure of the HMBPP-primed BTN3A1-BTN3A2-BTN2A1 complex
9II6 3.27 Å, Cryo-EM structure of the intracellular domains of BTN2A1-BTN3A1-BTN3A3
9JQ6 3.34 Å, Cryo-EM structure of BTN2A1 in complex with antagonist antibody TH002
9JQP 3.34 Å, Cryo-EM structure of the HMBPP-primed BTN3A1-BTN3A2-BTN2A1 in complex with agonist…

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