9KWZ: ICT01-BTN2A1/BTN3A1/BTN3A2 complex

Cryo-EM structure of the ICT01-BTN2A1/BTN3A1/BTN3A2 complex. Determined by electron microscopy at 3.7 Å resolution. Released 17 Dec 2025.

Method: Electron microscopy
Resolution: 3.7 Å
Organism: Homo sapiens
Chains: 6
Atoms: 10,022
Mol. weight: 272.4 kDa
Released: 17 Dec 2025

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

Secondary structure: helices and β-sheets

9KWZ contains 24 α-helices and 136 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: 3 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	39-41	3	1
β-strand	47-50	4	2
β-strand	63-66	4	1
β-strand	67	1	3
β-strand	74	1	3
β-strand	78	1	1
β-strand	83	1	1
β-strand	89	1	4
β-strand	92	1	4
β-strand	109-112	4	2
α-helix	117-119	3
β-strand	121-129	9	1
β-strand	132-142	11	1
α-helix	147-149	3
β-strand	150-157	8	5
β-strand	160-170	11	5
β-strand	175-179	5	6
β-strand	190-195	6	5
β-strand	201-207	7	5
β-strand	216-223	8	6
β-strand	228-235	8	6
α-helix	238-240	3

Chain B: 3 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	32-33	2	7
α-helix	38	1
β-strand	39-41	3	8
β-strand	47-53	7	7
β-strand	63-64	2	8
β-strand	67	1	8
β-strand	74	1	9
β-strand	78	1	8
β-strand	83	1	8
β-strand	88	1	9
β-strand	96-99	4	7
β-strand	107-112	6	7
β-strand	121-129	9	8
β-strand	132-142	11	8
β-strand	144	1	10
β-strand	150-157	8	11
β-strand	160-170	11	11
β-strand	171	1	10
β-strand	175-179	5	12
β-strand	185-186	2	12
β-strand	190-195	6	11
α-helix	196	1
α-helix	197-199	3
β-strand	201-208	8	11
β-strand	216-223	8	12
β-strand	228-235	8	12

Chain E: 5 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	33-34	2	13
β-strand	40-43	4	14
β-strand	49-54	6	13
β-strand	64-68	5	14
β-strand	75-80	6	14
β-strand	83-85	3	14
β-strand	97-100	4	13
β-strand	108-113	6	13
α-helix	118-120	3
β-strand	122-129	8	14
β-strand	134-144	11	14
β-strand	145	1	15
α-helix	148-150	3
β-strand	151-154	4	16
β-strand	162-171	10	16
β-strand	172	1	15
β-strand	176-180	5	17
β-strand	186-187	2	17
β-strand	190-191	2	16
α-helix	192-194	3
β-strand	195-196	2	16
α-helix	201	1
β-strand	202-210	9	16
β-strand	218-223	6	17
β-strand	230-237	8	17
α-helix	239-242	4

Chain F: 5 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	32-33	2	18
β-strand	40-41	2	19
α-helix	47-48	2
β-strand	54-55	2	18
α-helix	57	1
β-strand	65-69	5	19
β-strand	75-80	6	19
β-strand	83-85	3	19
α-helix	91-93	3
β-strand	99	1	20
β-strand	111	1	20
β-strand	122-125	4	19
β-strand	128-130	3	21
β-strand	133-135	3	21
β-strand	138-142	5	19
β-strand	151-155	5	17
β-strand	162-169	8	17
β-strand	176-181	6	16
β-strand	186	1	16
β-strand	191	1	17
α-helix	192-195	4
β-strand	203-210	8	17
β-strand	218-224	7	16
β-strand	229-236	8	16
α-helix	239-241	3

Chain H: 4 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	22
β-strand	10-12	3	23
β-strand	18-25	8	22
α-helix	29-31	3
β-strand	34-39	6	23
β-strand	45-51	7	23
β-strand	58-60	3	23
β-strand	68-73	6	22
β-strand	78-83	6	22
β-strand	92-99	8	23
β-strand	109-112	4	23
β-strand	116-120	5	23
β-strand	126	1	24
β-strand	129-133	5	25
α-helix	134-135	2
β-strand	144-154	11	25
β-strand	155	1	24
β-strand	159-162	4	26
β-strand	172-174	3	25
β-strand	185-194	10	25
α-helix	198-200	3
β-strand	203	1	27
β-strand	206-209	4	26
α-helix	211-213	3
β-strand	220	1	27

Chain L: 4 helices, 32 β-strands

Element	Residues	Length	Sheet
β-strand	5-7	3	28
β-strand	12	1	29
β-strand	19-21	3	30
β-strand	22-24	3	28
β-strand	29	1	31
β-strand	34-38	5	32
β-strand	45-49	5	32
β-strand	53-54	2	32
α-helix	55	1
β-strand	62-66	5	30
β-strand	68	1	31
β-strand	71-75	5	30
β-strand	85-89	5	32
α-helix	96	1
β-strand	98	1	32
β-strand	102-103	2	32
β-strand	105	1	29
β-strand	111	1	33
β-strand	114-115	2	34
β-strand	118	1	35
β-strand	121	1	25
α-helix	124-126	3
β-strand	129-135	7	35
β-strand	136-137	2	34
β-strand	139	1	36
β-strand	140	1	33
β-strand	146-149	4	37
β-strand	154-155	2	37
β-strand	159	1	35
β-strand	162-164	3	35
α-helix	165-166	2
β-strand	173	1	36
β-strand	174-182	9	35
β-strand	191-196	6	37
β-strand	205	1	37
β-strand	208-210	3	37

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Butyrophilin subfamily 2 member A1	A, B	protein	534	Homo sapiens	Q7KYR7 (AlphaFold model)
Butyrophilin subfamily 3 member A2	E	protein	340	Homo sapiens	P78410 (AlphaFold model)
Butyrophilin subfamily 3 member A1	F	protein	539	Homo sapiens	O00481 (AlphaFold model)
ICT01 heavy chain	H	protein	255	Homo sapiens
ICT01 light chain	L	protein	236	Homo sapiens

Sequence of entity 1 (A, B), FASTA

>9KWZ_1 Butyrophilin subfamily 2 member A1 (chains A, B)
MDMRVPAQLLGLLLLWLSGARCQFIVVGPTDPILATVGENTTLRCHLSPEKNAEDMEVRW
FRSQFSPAVFVYKGGRERTEEQMEEYRGRTTFVSKDISRGSVALVIHNITAQENGTYRCY
FQEGRSYDEAILHLVVAGLGSKPLISMRGHEDGGIRLECISRGWYPKPLTVWRDPYGGVA
PALKEVSMPDADGLFMVTTAVIIRDKSVRNMSCSINNTLLGQKKESVIFIPESFMPSVSP
CAVALPIIVVILMIPIAVCIYWINKLQKEKKILSGEKEFERETREIALKELEKERVQKEE
ELQVKEKLQEELRWRRTFLHAVDVVLDPDTAHPDLFLSEDRRSVRRCPFRHLGESVPDNP
ERFDSQPCVLGRESFASGKHYWEVEVENVIEWTVGVCRDSVERKGEVLLIPQNGFWTLEM
HKGQYRAVSSPDRILPLKESLCRVGVFLDYEAGDVSFYNMRDRSHIYTCPRSAFSVPVRP
FFRLGCEDSPIFICPALTGANGVTVPEEGLTLHRVGTHQSLGSSGMDYKDDDDK

Sequence of entity 2 (E), FASTA

>9KWZ_2 Butyrophilin subfamily 3 member A2 (chains E)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSNLHVEVKGYEDGGIHLECRSTGWYPQPQIQWSNAKGENI
PAVEAPVVADGVGLYEVAASVIMRGGSGEGVSCIIRNSLLGLEKTASISIADPFFRSAQP
WIAALAGTLPILLLLLAGASYFLWRQQKEITALSSEIESEQEMKEMGYAATEREISLRES
LQEELKRKKIQYLTRGEESSSDTNKSAGSSGMDYKDDDDK

Sequence of entity 3 (F), FASTA

>9KWZ_3 Butyrophilin subfamily 3 member A1 (chains F)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSDLHVDVKGYKDGGIHLECRSTGWYPQPQIQWSNNKGENI
PTVEAPVVADGVGLYAVAASVIMRGSSGEGVSCTIRSSLLGLEKTASISIADPFFRSAQR
WIAALAGTLPVLLLLLGGAGYFLWQQQEEKKTQFRKKKREQELREMAWSTMKQEQSTRVK
LLEELRWRSIQYASRGERHSAYNEWKKALFKPADVILDPKTANPILLVSEDQRSVQRAKE
PQDLPDNPERFNWHYCVLGCESFISGRHYWEVEVGDRKEWHIGVCSKNVQRKGWVKMTPE
NGFWTMGLTDGNKYRTLTEPRTNLKLPKPPKKVGVFLDYETGDISFYNAVDGSHIHTFLD
VSFSEALYPVFRILTLEPTALTICPAGSSGAWSHPQFEKGGGSGGGSGGSAWSHPQFEK

Sequence of entity 4 (H), FASTA

>9KWZ_4 ICT01 heavy chain (chains H)
MEFGLSWLFLVAILKGVQCQVQLVQSGAEVKKPGASVKLSCKASGYIFTRYYMYWVKQRP
GQGLEWIGEINPNNGGTKFNEKFKNRATLTVDKSISTAYMELSRLRSDDTAVYYCSREDD
YDGTPFAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV
SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVE
PKSCGGSHHHHHHHH

Sequence of entity 5 (L), FASTA

>9KWZ_5 ICT01 light chain (chains L)
MDMRVPAQLLGLLLLWLSGARCDIQMTQSPSSLSASVGDRVTITCHASQNINVWLSWYQQ
KPGKAPKLLIYKASNLHTGVPSRFSGSGSGTDFTFTISSLQPEDIATYYCQQGQTYPYTF
GQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGN
SQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

Primary citation

Cryo-EM structure of the ICT01-BTN2A1/BTN3A1/BTN3A2 complex at 3.7 Angstroms reolution. Xin, W.Z., Huang, B.D., Zhou, Q. To be published.

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…

Browse structure collections

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