9C42: Human MR1-ellagic acid

Structure of human MR1-ellagic acid in complex with human MAIT A-F7 TCR. Determined by X-ray diffraction at 2.69 Å resolution. Released 11 Jun 2025.

Method: X-ray diffraction
Resolution: 2.69 Å
Organism: Homo sapiens
Chains: 8
Atoms: 12,686
Mol. weight: 189.27 kDa
Ligands: REF
Released: 11 Jun 2025

Explore 9C42 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9C42 contains 53 α-helices and 148 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: 9 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-12	10	1
α-helix	15-16	2
β-strand	22-28	7	1
β-strand	31-37	7	1
β-strand	44-45	2	1
α-helix	48-51	4
α-helix	56-84	29
β-strand	91-100	10	1
β-strand	106-114	9	1
β-strand	117-123	7	1
β-strand	128-131	4	1
α-helix	134-143	10
α-helix	147-155	9
α-helix	156-160	5
α-helix	161-171	11
α-helix	173-176	4
β-strand	180	1	2
β-strand	183-189	7	3
β-strand	197-205	9	3
β-strand	206	1	2
β-strand	211-216	6	4
β-strand	219	1	4
β-strand	225-227	3	3
α-helix	228-230	3
β-strand	231-232	2	3
β-strand	238-245	8	3
β-strand	254-260	7	4
β-strand	263-268	6	4

Chain B: 3 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	3	1	5
α-helix	4-5	2
β-strand	6-11	6	6
β-strand	21-30	10	6
β-strand	31	1	5
β-strand	36-41	6	7
β-strand	44-45	2	7
α-helix	46	1
β-strand	50-51	2	6
α-helix	52-54	3
β-strand	55-56	2	6
β-strand	62-70	9	6
β-strand	78-83	6	7
β-strand	91-94	4	7

Chain C: 11 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-12	10	8
α-helix	15-16	2
β-strand	22-28	7	8
β-strand	31-37	7	8
β-strand	43-45	3	8
α-helix	48-51	4
α-helix	56-84	29
β-strand	91-100	10	8
β-strand	106-114	9	8
β-strand	117-123	7	8
β-strand	128-131	4	8
α-helix	134-144	11
α-helix	147-155	9
α-helix	156-160	5
α-helix	161-171	11
α-helix	173-176	4
β-strand	180	1	9
α-helix	181-182	2
β-strand	183-190	8	10
β-strand	196-205	10	10
β-strand	206	1	9
β-strand	211-216	6	11
β-strand	220-221	2	11
α-helix	222	1
β-strand	226-227	2	10
α-helix	228-230	3
β-strand	231-232	2	10
β-strand	238-245	8	10
β-strand	254-260	7	11
β-strand	263-268	6	11

Chain D: 6 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	3-5	3	12
β-strand	9-13	5	13
β-strand	18-25	8	12
β-strand	32-37	6	13
β-strand	44-49	6	13
β-strand	53-57	5	12
β-strand	60-65	6	12
β-strand	70-75	6	12
α-helix	80-82	3
β-strand	84-91	8	13
α-helix	96	1
β-strand	97-99	3	13
α-helix	100	1
β-strand	103-108	6	13
β-strand	117-121	5	14
β-strand	123	1	15
β-strand	131-135	5	14
α-helix	143-146	4
β-strand	151-153	3	14
α-helix	154-156	3
β-strand	159-161	3	16
β-strand	166-168	3	16
β-strand	170-175	6	14
α-helix	182-185	4
β-strand	196	1	14

Chain E: 7 helices, 24 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	17
β-strand	10-14	5	18
β-strand	19-25	7	17
β-strand	31-37	7	18
β-strand	44-51	8	18
β-strand	54-57	4	18
β-strand	64-70	7	17
β-strand	73-78	6	17
α-helix	83-85	3
β-strand	87-94	8	18
α-helix	102-104	3
β-strand	105-106	2	18
β-strand	110-115	6	18
α-helix	118-120	3
β-strand	122	1	19
α-helix	123-124	2
β-strand	125-129	5	15
α-helix	130-132	3
α-helix	133-139	7
β-strand	141-151	11	15
β-strand	152	1	19
β-strand	156-162	7	20
β-strand	165-167	3	20
β-strand	171-173	3	15
β-strand	178-179	2	15
β-strand	189-198	10	15
α-helix	199-203	5
β-strand	208-215	8	20
β-strand	218	1	21
β-strand	232	1	21
β-strand	234-241	8	20

Chain F: 3 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	3	1	22
α-helix	4-5	2
β-strand	6-11	6	23
β-strand	21-30	10	23
β-strand	31	1	22
β-strand	35-41	7	24
β-strand	44-45	2	24
α-helix	46	1
β-strand	50-51	2	23
α-helix	52-54	3
β-strand	55-56	2	23
β-strand	62-70	9	23
β-strand	78-84	7	24
β-strand	91-94	4	24

Chain G: 6 helices, 18 β-strands

Element	Residues	Length	Sheet
β-strand	3-5	3	25
β-strand	9-13	5	26
β-strand	18-25	8	25
β-strand	32-37	6	26
β-strand	44-49	6	26
β-strand	53-57	5	25
β-strand	60-65	6	25
β-strand	70-75	6	25
α-helix	80-82	3
β-strand	84-91	8	26
β-strand	97-99	3	26
β-strand	103-108	6	26
β-strand	117-120	4	27
α-helix	121	1
β-strand	122	1	28
α-helix	123	1
β-strand	130-135	6	27
α-helix	144-146	3
β-strand	152-153	2	27
β-strand	157-161	5	27
α-helix	162-164	3
β-strand	166-175	10	27
α-helix	182-184	3
β-strand	196	1	27

Chain H: 8 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	29
β-strand	10-14	5	30
β-strand	19-21	3	31
β-strand	22-25	4	29
β-strand	31-37	7	30
β-strand	44-51	8	30
β-strand	54-57	4	30
β-strand	64-67	4	31
β-strand	73	1	29
β-strand	75-78	4	31
α-helix	83-85	3
β-strand	87-94	8	30
α-helix	102-104	3
β-strand	105-106	2	30
β-strand	110-115	6	30
β-strand	122	1	32
α-helix	123-124	2
β-strand	125-129	5	33
β-strand	130	1	28
α-helix	131-132	2
α-helix	133-139	7
β-strand	141-151	11	33
β-strand	152	1	32
β-strand	156-162	7	34
β-strand	165-167	3	34
β-strand	171-173	3	33
α-helix	177	1
β-strand	178-179	2	33
β-strand	189-198	10	33
α-helix	199-202	4
β-strand	208-215	8	34
β-strand	218	1	35
α-helix	229-230	2
β-strand	232	1	35
β-strand	234-241	8	34

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Major histocompatibility complex class I-related gene protein	A, C	protein	271	Homo sapiens	Q95460 (AlphaFold model)
Beta-2-microglobulin	B, F	protein	100	Homo sapiens	P61769 (AlphaFold model)
TRA@ protein	D, G	protein	204	Homo sapiens	Q6P4G7 (AlphaFold model)
MAIT T-cell receptor beta chain	E, H	protein	246	Homo sapiens

Sequence of entity 1 (A, C), FASTA

>9C42_1 Major histocompatibility complex class I-related gene protein (chains A, C)
MRTHSLRYFRLGVSDPIHGVPEFISVGYVDSHPITTYDSVTRQKEPRAPWMAENLAPDHW
ERYTQLLRGWQQMFKVELKRLQRHYNHSGSHTYQRMIGCELLEDGSTTGFLQYAYDGQDF
LIFNKDTLSWLAVDNVAHTIKQAWEANQHELLYQKNWLEEECIAWLKRFLEYGKDTLQRT
EPPLVRVNRKETFPGVTALFCKAHGFYPPEIYMTWMKNGEEIVQEIDYGDILPSGDGTYQ
AWASIELDPQSSNLYSCHVEHSGVHMVLQVP

Sequence of entity 2 (B, F), FASTA

>9C42_2 Beta-2-microglobulin (chains B, F)
MIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKD
WSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

Sequence of entity 3 (D, G), FASTA

>9C42_3 TRA@ protein (chains D, G)
MGQNIDQPTEMTATEGAIVQINCTYQTSGFNGLFWYQQHAGEAPTFLSYNVLDGLEEKGR
FSSFLSRSKGYSYLLLKELQMKDSASYLCAVKDSNYQLIWGAGTKLIIKPDIQNPDPAVY
QLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKCVLDMRSMDFKSNSAVAWSNKSD
FACANAFNNSIIPEDTFFPSPESS

Sequence of entity 4 (E, H), FASTA

>9C42_4 MAIT T-cell receptor beta chain (chains E, H)
MNAGVTQTPKFQVLKTGQSMTLQCAQDMNHNSMYWYRQDPGMGLRLIYYSASEGTTDKGE
VPNGYNVSRLNKREFSLRLESAAPSQTSVYFCASSVWTGEGSGELFFGEGSRLTVLEDLK
NVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVCTDPQPLK
EQPALNDSRYALSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAE
AWGRAD

Ligands and cofactors

ID	Name	Formula	Copies
REF	2,3,7,8-tetrahydroxychromeno[5,4,3-cde]chromene-5,10-dione	C14 H6 O8	2

Water and common crystallization additives (NA, ACY, CL, GOL) are not listed.

Primary citation

Ellagic acid metabolism as a source of dietary MR1 ligands. O'Sullivan, D., Wang, C.J.H., Tang, J.S. et al. J Immunol (2026) 215. DOI 10.1093/jimmun/vkaf346 · PubMed

Other PDB entries of the same protein (UniProt Q95460 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6PUD 1.8 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-5'OH-Pentyl-5-OP-U
6PUG 1.8 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-2`OH-Ethyl-5-OP-U
6PUL 1.84 Å, Structure of human MAIT A-F7 TCR in complex with human MR1 3'D-5-OP-RU
7ZT7 1.84 Å, Structure of E8 TCR in complex in human MR1 bound to 5FSA
6PUC 1.85 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-5-OP-RU
6PUH 1.88 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-Ribityl-less
6W9U 1.89 Å, Structure of human MAIT A-F7 TCR in complex with patient MR1-R9H-Ac-6-FP
4L4V 1.9 Å, Structure of human MAIT TCR in complex with human MR1-RL-6-Me-7-OH
5U6Q 1.9 Å, Structure of human MR1-3-F-SA in complex with human MAIT A-F7 TCR
6PUE 1.9 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-4'D-5-OP-RU
6PUF 1.92 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-5'D-5-OP-RU
6PUJ 1.92 Å, Structure of human MAIT A-F7 TCR in complex with human MR1-3`OH-Propyl-5-OP-U

Browse structure collections

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