9OFR: PDB entry 9OFR

Crystal structure of the human IGA1 fc fragment-fc-alpha receptor (CD89) complex. Determined by X-ray diffraction at 2.65 Å resolution. Released 6 May 2026.

Method: X-ray diffraction
Resolution: 2.65 Å
Organism: Homo sapiens
Chains: 8
Atoms: 13,022
Mol. weight: 190.89 kDa
Ligands: NAG
Released: 6 May 2026

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

Secondary structure: helices and β-sheets

9OFR contains 46 α-helices and 160 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, 20 β-strands

Element	Residues	Length	Sheet
β-strand	245-249	5	1
α-helix	250-252	3
α-helix	253-257	5
β-strand	264-269	6	1
β-strand	278-281	4	2
β-strand	290-291	2	1
β-strand	295	1	3
β-strand	303	1	3
β-strand	304-308	5	1
α-helix	312-316	5
β-strand	321-327	7	2
β-strand	331-338	8	2
β-strand	345	1	4
β-strand	348-352	5	5
α-helix	353-355	3
α-helix	356-361	6
β-strand	364-374	11	5
β-strand	375	1	4
β-strand	380-385	6	6
β-strand	388-389	2	6
α-helix	390-391	2
α-helix	392-394	3
β-strand	395-397	3	5
β-strand	401-402	2	5
α-helix	403-404	2
β-strand	411-420	10	5
α-helix	421-426	6
β-strand	430-435	6	6
β-strand	443-448	6	6

Chain B: 10 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	245-249	5	13
α-helix	250-252	3
α-helix	253-258	6
β-strand	263-271	9	13
β-strand	278-281	4	14
β-strand	285	1	15
β-strand	287	1	15
β-strand	290-291	2	13
β-strand	295	1	13
β-strand	302-309	8	13
α-helix	312-317	6
α-helix	319	1
β-strand	320-326	7	14
β-strand	334-339	6	14
β-strand	345	1	16
α-helix	346-347	2
β-strand	348-352	5	17
α-helix	353-355	3
α-helix	356-361	6
β-strand	364-374	11	17
β-strand	375	1	16
β-strand	380-385	6	18
β-strand	388-389	2	18
α-helix	390-391	2
α-helix	392-394	3
β-strand	395-397	3	17
β-strand	401-402	2	17
β-strand	411-420	10	17
α-helix	421-426	6
β-strand	430-435	6	18
β-strand	443-448	6	18

Chain C: 1 helix, 20 β-strands

Element	Residues	Length	Sheet
β-strand	10-12	3	7
β-strand	17-19	3	8
β-strand	24-28	5	7
β-strand	36-43	8	9
β-strand	46-54	9	9
β-strand	63-66	4	7
α-helix	71-73	3
β-strand	75-83	9	9
β-strand	87-90	4	9
β-strand	94-96	3	9
β-strand	97-99	3	8
β-strand	106-109	4	10
β-strand	114	1	11
β-strand	122-126	5	10
β-strand	134-139	6	12
β-strand	149-150	2	12
β-strand	155-158	4	10
β-strand	168-175	8	12
β-strand	182	1	8
β-strand	190-192	3	12
β-strand	193	1	11

Chain D: 3 helices, 21 β-strands

Element	Residues	Length	Sheet
α-helix	7-9	3
β-strand	10-12	3	19
β-strand	17-19	3	20
β-strand	24-28	5	19
α-helix	29-30	2
β-strand	36-43	8	21
β-strand	46-54	9	21
β-strand	63-66	4	19
α-helix	71-73	3
β-strand	75-83	9	21
β-strand	87-96	10	21
β-strand	97-99	3	20
β-strand	106-109	4	22
β-strand	114-115	2	23
β-strand	122-126	5	22
β-strand	134-139	6	24
β-strand	148-150	3	24
β-strand	155-158	4	22
β-strand	168	1	25
β-strand	170-175	6	24
β-strand	182	1	20
β-strand	183	1	24
β-strand	192	1	25
β-strand	193-194	2	23

Chain E: 9 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	245-249	5	26
α-helix	250-252	3
α-helix	253-257	5
β-strand	264-271	8	26
β-strand	278-281	4	27
β-strand	290-291	2	26
β-strand	302-308	7	26
α-helix	312-316	5
β-strand	321-322	2	28
β-strand	323-326	4	27
α-helix	333	1
β-strand	334	1	27
β-strand	337-338	2	28
β-strand	345	1	29
β-strand	348-352	5	30
α-helix	353-354	2
α-helix	359-361	3
β-strand	364-374	11	30
β-strand	375	1	29
β-strand	380-385	6	31
β-strand	388-389	2	31
α-helix	390-391	2
α-helix	392-394	3
β-strand	395-397	3	30
β-strand	401-402	2	30
β-strand	411-420	10	30
α-helix	421-426	6
β-strand	430-435	6	31
β-strand	443-448	6	31

Chain F: 2 helices, 20 β-strands

Element	Residues	Length	Sheet
α-helix	7-9	3
β-strand	10-12	3	32
β-strand	17-19	3	33
β-strand	24-28	5	32
β-strand	34-43	10	34
β-strand	46-54	9	34
β-strand	63-66	4	32
α-helix	71-73	3
β-strand	75-83	9	34
β-strand	87-96	10	34
β-strand	97-99	3	33
β-strand	106-107	2	35
β-strand	115	1	36
β-strand	122-126	5	35
β-strand	134-139	6	37
β-strand	148-150	3	37
β-strand	155-158	4	35
β-strand	169-175	7	37
β-strand	182	1	33
β-strand	183	1	37
β-strand	190-191	2	37
β-strand	194	1	36

Chain G: 10 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	245-249	5	38
α-helix	250-252	3
α-helix	253-258	6
β-strand	264-271	8	38
β-strand	278-281	4	39
β-strand	290-291	2	38
β-strand	295-297	3	38
β-strand	300-308	9	38
α-helix	312-316	5
β-strand	321-326	6	39
α-helix	333	1
β-strand	334-338	5	39
β-strand	345	1	40
β-strand	348-352	5	41
α-helix	353-355	3
α-helix	356-361	6
β-strand	364-374	11	41
β-strand	375	1	40
β-strand	380-385	6	42
β-strand	388-389	2	42
α-helix	390-391	2
α-helix	392-394	3
β-strand	395-397	3	41
β-strand	401-402	2	41
α-helix	403-405	3
β-strand	411-420	10	41
α-helix	421-426	6
β-strand	430-435	6	42
β-strand	443-448	6	42

Chain H: 2 helices, 19 β-strands

Element	Residues	Length	Sheet
α-helix	7-9	3
β-strand	10-12	3	43
β-strand	17-19	3	44
β-strand	23-28	6	43
α-helix	29-30	2
β-strand	36-43	8	45
β-strand	46-54	9	45
β-strand	63-67	5	43
β-strand	75-83	9	45
β-strand	87-96	10	45
β-strand	97-99	3	44
β-strand	106-108	3	46
β-strand	115	1	47
β-strand	122-126	5	46
β-strand	134-139	6	48
β-strand	148-150	3	48
β-strand	154-158	5	46
β-strand	168-175	8	48
β-strand	182-183	2	44
β-strand	190-192	3	48
β-strand	194	1	47

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Isoform 1 of Immunoglobulin heavy constant alpha 1	A, B, E, G	protein	214	Homo sapiens	P01876 (AlphaFold model)
Immunoglobulin alpha Fc receptor	C, D, F, H	protein	207	Homo sapiens	P24071 (AlphaFold model)

Sequence of entity 1 (A, B, E, G), FASTA

>9OFR_1 Isoform 1 of Immunoglobulin heavy constant alpha 1 (chains A, B, E, G)
ACHPRLSLHRPALEDLLLGSEANLTCTLTGLRDASGVTFTWTPSSGKSAVQGPPERDLCG
CYSVSSVLPGCAEPWNHGKTFTCTAAYPESKTPLTATLSKSGNTFRPEVHLLPPPSEELA
LNELVTLTCLARGFSPKDVLVRWLQGSQELPREKYLTWASRQEPSQGTTTFAVTSILRVA
AEDWKKGDTFSCMVGHEALPLAFTQKTIDRLAGK

Sequence of entity 2 (C, D, F, H), FASTA

>9OFR_2 Immunoglobulin alpha Fc receptor (chains C, D, F, H)
QEGDFPMPFISAKSSPVIPLDGSVKIQCQAIREAYLTQLMIIKNSTYREIGRRLKFWNET
DPEFVIDHMDANKAGRYQCQYRIGHYRFRYSDTLELVVTGLYGKPFLSADRGLVLMPGEN
ISLTCSSAHIPFDRFSLAKEGELSLPQHQSGEHPANFSLGPVDLNVSGIYRCYGWYNRSP
YLWSFPSNALELVVTAIDGRAHHHHHH

Ligands and cofactors

ID	Name	Formula	Copies
NAG	2-acetamido-2-deoxy-beta-D-glucopyranose	C8 H15 N O6	14

Primary citation

CRYSTAL STRUCTURE OF THE HUMAN IGA1 FC FRAGMENT-FC-ALPHA RECEPTOR (CD89) COMPLEX. Korzeniowski, M., Tolbert, W.D., Pazgier, M. To be published.

Other PDB entries of the same protein (UniProt P01876 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9R2E 2.54 Å, Structure of ARGX-121 Fab fragment in complex with the Fc fragment of IgA1
6UE7 2.9 Å, Structure of dimeric sIgA complex
1OW0 3.1 Å, Crystal structure of human FcaRI bound to IgA1-Fc
8SKV 3.1 Å, Structure of human SIgA1 in complex with Streptococcus pyogenes protein M4 (Arp4)
6LX3 3.15 Å, Cryo-EM structure of human secretory immunoglobulin A
2QEJ 3.2 Å, Crystal structure of a Staphylococcus aureus protein (SSL7) in complex with Fc of human…
8SKU 3.2 Å, Structure of human SIgA1 in complex with human CD89 (FcaR1)
6LXW 3.27 Å, Cryo-EM structure of human secretory immunoglobulin A in complex with the N-terminal…
9MBZ 3.3 Å, Cryo-EM structure of human FcRL4 bound to IgA-Fc/J
7UVL 3.56 Å, IgA1 Protease with IgA1 substrate
6XJA 4.0 Å, Streptococcus Pneumoniae IgA1 Protease with IgA1 substrate
1IGA Model of human IGA1 determined by solution scattering curve-fitting and homology modelling

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