9L1Q: ICT01-BTN2A1/BTN3A1/BTN3A2 complex

Cryo-EM structure of the ICT01-BTN2A1/BTN3A1/BTN3A2 complex (2 fabs). Determined by electron microscopy at 4.0 Å resolution. Released 17 Dec 2025.

Method: Electron microscopy
Resolution: 4.0 Å
Organism: Homo sapiens
Chains: 8
Atoms: 13,358
Mol. weight: 326.16 kDa
Released: 17 Dec 2025

Explore 9L1Q in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9L1Q contains 33 α-helices and 179 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 A: 2 helices, 26 β-strands

Element	Residues	Length	Sheet
β-strand	31	1	1
β-strand	41	1	2
β-strand	47-48	2	3
β-strand	51-52	2	4
β-strand	54	1	1
α-helix	56	1
β-strand	63-67	5	5
β-strand	74-78	5	5
β-strand	79	1	6
β-strand	82	1	6
β-strand	88	1	5
β-strand	107-108	2	4
β-strand	111-112	2	3
β-strand	121	1	7
β-strand	126-128	3	5
β-strand	134	1	5
β-strand	140	1	7
β-strand	142	1	2
α-helix	148-149	2
β-strand	150	1	8
β-strand	156-157	2	9
β-strand	160-161	2	9
β-strand	165-170	6	8
β-strand	175-179	5	10
β-strand	190-195	6	8
β-strand	201-206	6	8
β-strand	216-223	8	10
β-strand	228-235	8	10

Chain B: 3 helices, 26 β-strands

Element	Residues	Length	Sheet
β-strand	32-33	2	11
β-strand	39-41	3	12
β-strand	47-53	7	11
β-strand	63-66	4	13
β-strand	76-79	4	13
β-strand	82-83	2	13
α-helix	85-87	3
β-strand	96-99	4	11
β-strand	107-112	6	11
β-strand	121	1	12
β-strand	124-129	6	13
β-strand	132-137	6	13
β-strand	140-142	3	12
β-strand	144	1	14
β-strand	150-151	2	15
β-strand	157	1	16
β-strand	160	1	16
β-strand	162	1	17
β-strand	165-170	6	15
β-strand	171	1	14
β-strand	175-179	5	18
β-strand	186	1	18
β-strand	191-195	5	15
α-helix	197-199	3
α-helix	200	1
β-strand	201-205	5	15
β-strand	208	1	17
β-strand	216-223	8	18
β-strand	228-235	8	18

Chain E: 5 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	33-34	2	19
α-helix	35-36	2
α-helix	39	1
β-strand	40-43	4	20
β-strand	48-54	7	19
β-strand	64-69	6	20
β-strand	75-79	5	20
β-strand	80	1	21
β-strand	83	1	21
β-strand	97-100	4	19
β-strand	108-113	6	19
α-helix	118-120	3
β-strand	122-129	8	20
β-strand	134-144	11	20
α-helix	148-150	3
β-strand	151-154	4	22
β-strand	164-171	8	22
β-strand	176-180	5	23
β-strand	186	1	23
β-strand	190-191	2	22
β-strand	195-196	2	22
β-strand	202-208	7	22
β-strand	219-223	5	23
β-strand	230-236	7	23
α-helix	239-241	3

Chain F: 4 helices, 24 β-strands

Element	Residues	Length	Sheet
β-strand	34	1	24
β-strand	40-41	2	25
β-strand	51	1	26
β-strand	53	1	24
β-strand	65	1	27
β-strand	66-68	3	28
β-strand	79	1	27
β-strand	80	1	29
β-strand	83	1	29
α-helix	91-93	3
β-strand	100-103	4	26
β-strand	108-110	3	26
α-helix	118-120	3
β-strand	123-128	6	28
β-strand	135-140	6	28
β-strand	141-142	2	25
β-strand	151-154	4	23
β-strand	158	1	30
β-strand	161	1	30
β-strand	162-171	10	23
α-helix	174-176	3
β-strand	178-181	4	22
β-strand	191	1	23
β-strand	195-196	2	23
β-strand	202-210	9	23
β-strand	218-224	7	22
β-strand	228-237	10	22
α-helix	239-241	3

Chain h: 8 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	3	1	42
α-helix	5	1
β-strand	6	1	43
α-helix	7-9	3
β-strand	10	1	44
β-strand	18-23	6	43
β-strand	25	1	42
β-strand	34-39	6	44
β-strand	49-51	3	44
β-strand	58	1	44
α-helix	62-64	3
β-strand	68-73	6	43
β-strand	78-83	6	43
α-helix	88-90	3
β-strand	92-98	7	44
β-strand	111-112	2	44
β-strand	116-118	3	44
β-strand	129-132	4	45
α-helix	133-134	2
α-helix	137-140	4
β-strand	144-154	11	45
β-strand	160-163	4	46
β-strand	168	1	46
β-strand	173-174	2	45
α-helix	175-177	3
β-strand	185-194	10	45
β-strand	204-209	6	46
β-strand	214-219	6	46
α-helix	220-221	2

Chain H: 3 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	31
β-strand	10-12	3	32
β-strand	18-25	8	31
α-helix	29-31	3
β-strand	34-39	6	32
β-strand	45-51	7	32
β-strand	58-60	3	32
β-strand	68-73	6	31
β-strand	78-83	6	31
β-strand	92-99	8	32
β-strand	109-112	4	32
β-strand	116-120	5	32
β-strand	126	1	33
β-strand	129-132	4	34
α-helix	134-136	3
α-helix	138-141	4
β-strand	144-154	11	34
β-strand	155	1	33
β-strand	159-163	5	35
β-strand	168	1	35
β-strand	173-174	2	34
β-strand	178-180	3	34
β-strand	184-194	11	34
β-strand	204	1	36
β-strand	205-209	5	35
β-strand	219	1	36

Chain l: 4 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	47
β-strand	10-11	2	48
β-strand	19-29	11	47
β-strand	33-38	6	48
β-strand	44-49	6	48
β-strand	53-54	2	48
α-helix	55	1
β-strand	62-66	5	47
β-strand	68-75	8	47
β-strand	85-90	6	48
β-strand	102-104	3	48
α-helix	110-111	2
β-strand	116-118	3	49
β-strand	129-137	9	49
β-strand	145-150	6	50
β-strand	154	1	50
β-strand	159-164	6	49
β-strand	174-182	9	49
α-helix	183-187	5
β-strand	191-197	7	50
α-helix	204	1
β-strand	205-210	6	50

Chain L: 4 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	37
β-strand	10-12	3	38
β-strand	19-21	3	39
β-strand	22-29	8	37
β-strand	33-38	6	38
β-strand	45-49	5	38
β-strand	53-54	2	38
α-helix	55	1
β-strand	62-65	4	39
β-strand	68-70	3	37
β-strand	72-75	4	39
β-strand	85-90	6	38
α-helix	96	1
β-strand	98	1	38
β-strand	102-105	4	38
β-strand	118	1	40
α-helix	123-126	4
β-strand	129-139	11	40
β-strand	144-150	7	41
β-strand	153	1	41
β-strand	162-164	3	40
β-strand	173-182	10	40
β-strand	191-198	8	41
α-helix	204	1
β-strand	205-210	6	41

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, h	protein	255	Homo sapiens
ICT01 light chain	L, l	protein	236	Homo sapiens

Sequence of entity 1 (A, B), FASTA

>9L1Q_1 Butyrophilin subfamily 2 member A1 (chains A, B)
MDMRVPAQLLGLLLLWLSGARCQFIVVGPTDPILATVGENTTLRCHLSPEKNAEDMEVRW
FRSQFSPAVFVYKGGRERTEEQMEEYRGRTTFVSKDISRGSVALVIHNITAQENGTYRCY
FQEGRSYDEAILHLVVAGLGSKPLISMRGHEDGGIRLECISRGWYPKPLTVWRDPYGGVA
PALKEVSMPDADGLFMVTTAVIIRDKSVRNMSCSINNTLLGQKKESVIFIPESFMPSVSP
CAVALPIIVVILMIPIAVCIYWINKLQKEKKILSGEKEFERETREIALKELEKERVQKEE
ELQVKEKLQEELRWRRTFLHAVDVVLDPDTAHPDLFLSEDRRSVRRCPFRHLGESVPDNP
ERFDSQPCVLGRESFASGKHYWEVEVENVIEWTVGVCRDSVERKGEVLLIPQNGFWTLEM
HKGQYRAVSSPDRILPLKESLCRVGVFLDYEAGDVSFYNMRDRSHIYTCPRSAFSVPVRP
FFRLGCEDSPIFICPALTGANGVTVPEEGLTLHRVGTHQSLGSSGMDYKDDDDK

Sequence of entity 2 (E), FASTA

>9L1Q_2 Butyrophilin subfamily 3 member A2 (chains E)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSNLHVEVKGYEDGGIHLECRSTGWYPQPQIQWSNAKGENI
PAVEAPVVADGVGLYEVAASVIMRGGSGEGVSCIIRNSLLGLEKTASISIADPFFRSAQP
WIAALAGTLPILLLLLAGASYFLWRQQKEITALSSEIESEQEMKEMGYAATEREISLRES
LQEELKRKKIQYLTRGEESSSDTNKSAGSSGMDYKDDDDK

Sequence of entity 3 (F), FASTA

>9L1Q_3 Butyrophilin subfamily 3 member A1 (chains F)
MDMRVPAQLLGLLLLWLSGARCQFSVLGPSGPILAMVGEDADLPCHLFPTMSAETMELKW
VSSSLRQVVNVYADGKEVEDRQSAPYRGRTSILRDGITAGKAALRIHNVTASDSGKYLCY
FQDGDFYEKALVELKVAALGSDLHVDVKGYKDGGIHLECRSTGWYPQPQIQWSNNKGENI
PTVEAPVVADGVGLYAVAASVIMRGSSGEGVSCTIRSSLLGLEKTASISIADPFFRSAQR
WIAALAGTLPVLLLLLGGAGYFLWQQQEEKKTQFRKKKREQELREMAWSTMKQEQSTRVK
LLEELRWRSIQYASRGERHSAYNEWKKALFKPADVILDPKTANPILLVSEDQRSVQRAKE
PQDLPDNPERFNWHYCVLGCESFISGRHYWEVEVGDRKEWHIGVCSKNVQRKGWVKMTPE
NGFWTMGLTDGNKYRTLTEPRTNLKLPKPPKKVGVFLDYETGDISFYNAVDGSHIHTFLD
VSFSEALYPVFRILTLEPTALTICPAGSSGAWSHPQFEKGGGSGGGSGGSAWSHPQFEK

Sequence of entity 4 (H, h), FASTA

>9L1Q_4 ICT01 heavy chain (chains H, h)
MEFGLSWLFLVAILKGVQCQVQLVQSGAEVKKPGASVKLSCKASGYIFTRYYMYWVKQRP
GQGLEWIGEINPNNGGTKFNEKFKNRATLTVDKSISTAYMELSRLRSDDTAVYYCSREDD
YDGTPFAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV
SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVE
PKSCGGSHHHHHHHH

Sequence of entity 5 (L, l), FASTA

>9L1Q_5 ICT01 light chain (chains L, l)
MDMRVPAQLLGLLLLWLSGARCDIQMTQSPSSLSASVGDRVTITCHASQNINVWLSWYQQ
KPGKAPKLLIYKASNLHTGVPSRFSGSGSGTDFTFTISSLQPEDIATYYCQQGQTYPYTF
GQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGN
SQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

Primary citation

Cryo-EM structure of the ICT01-BTN2A1/BTN3A1/BTN3A2 complex at 4 Angtroms resolution (2 fabs). 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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