9OC6: Receptor FcRn

Crystal structure of receptor FcRn bound to Human Astrovirus 6 spike. Determined by X-ray diffraction at 2.97 Å resolution. Released 19 Nov 2025.

Method: X-ray diffraction
Resolution: 2.97 Å
Organisms: Homo sapiens, Human astrovirus 6
Chains: 3
Atoms: 4,351
Mol. weight: 70.09 kDa
Released: 19 Nov 2025

Explore 9OC6 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9OC6 contains 17 α-helices and 48 β-strands across 3 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: 8 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	4-11	8	10
α-helix	14-15	2
α-helix	23-25	3
β-strand	26-27	2	11
α-helix	33-35	3
β-strand	37-42	6	10
β-strand	45-48	4	10
β-strand	51-61	11	10
β-strand	67-68	2	10
α-helix	69-74	6
β-strand	78-81	4	10
β-strand	85-98	14	10
β-strand	103-114	12	10
β-strand	118-125	8	11
β-strand	127-128	2	12
β-strand	140	1	13
β-strand	141-142	2	12
β-strand	147-153	7	11
β-strand	158-168	11	10
α-helix	171-173	3
α-helix	175-177	3
α-helix	181-183	3
β-strand	188	1	13
α-helix	200-202	3
β-strand	206-212	7	10

Chain C: 8 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	6-14	9	1
α-helix	17-18	2
β-strand	24-30	7	1
β-strand	33-39	7	1
β-strand	46-47	2	1
α-helix	49-52	4
α-helix	58-81	24
β-strand	89-97	9	1
β-strand	98	1	2
β-strand	104	1	2
β-strand	107-112	6	1
β-strand	115-121	7	1
β-strand	126-128	3	1
α-helix	134-142	9
α-helix	147-153	7
α-helix	154-158	5
α-helix	159-166	8
β-strand	178	1	3
α-helix	179-180	2
β-strand	181-184	4	4
β-strand	198-203	6	4
β-strand	204	1	3
β-strand	208-209	2	5
β-strand	225-228	4	4
β-strand	234-238	5	4
β-strand	252-254	3	6
β-strand	255-256	2	5
β-strand	263-265	3	6

Chain D: 1 helix, 11 β-strands

Element	Residues	Length	Sheet
β-strand	3	1	7
α-helix	4-5	2
β-strand	6-11	6	8
β-strand	21-30	10	8
β-strand	31	1	7
β-strand	36-41	6	9
β-strand	44-45	2	9
β-strand	50-51	2	8
β-strand	55-56	2	8
β-strand	62-70	9	8
β-strand	78-83	6	9
β-strand	91-94	4	9

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
IgG receptor FcRn large subunit p51	C	protein	274	Homo sapiens	P55899 (AlphaFold model)
Beta-2-microglobulin	D	protein	99	Homo sapiens	P61769 (AlphaFold model)
Capsid polyprotein VP90	A	protein	244	Human astrovirus 6	A0A3G6VE58

Sequence of entity 1 (C), FASTA

>9OC6_1 IgG receptor FcRn large subunit p51 (chains C)
AESHLSLLYHLTAVSSPAPGTPAFWVSGWLGPQQYLSYNSLRGEAEPCGAWVWENQVSWY
WEKETTDLRIKEKLFLEAFKALGGKGPYTLQGLLGCELGPDNTSVPTAKFALNGEEFMNF
DLKQGTWGGDWPEALAISQRWQQQDKAANKELTFLLFSCPHRLREHLERGRGNLEWKEPP
SMRLKARPSSPGFSVLTCSAFSFYPPELQLRFLRNGLAAGTGQGDFGPNSDGSFHASSSL
TVKSGDEHHYCCIVQHAGLAQPLRVELESPAKSS

Sequence of entity 2 (D), FASTA

>9OC6_2 Beta-2-microglobulin (chains D)
IQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKDW
SFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

Sequence of entity 3 (A), FASTA

>9OC6_3 Capsid polyprotein VP90 (chains A)
MGETLKVLLTVGNPISPNETNKQTWVNKTIEPPGAVVKIGRDTQHYCTMNGFTLITKVDW
FTEEFQPSEEPAPVQGLMVLLDNHKKADVYAAQQYKNPITNDKQQVTSVFLVRVNEGFQV
TNHLSYFYRNSVNTDAVENIKIRSATRHTTVRFNQGSWYLLTSTVLHTGPPVSGWLWMNQ
ELQNDQAYIIDQGIMHLITPPPVSSQIYFEMATLVPGSGLNDIFEAQKIEWHEGHHHHHH
HHHH

Primary citation

Structural hijacking of FcRn by human astrovirus spikes reveals conserved epitopes for broad-spectrum antivirals. Agrawal, S., Jain, M., Marinelli, D. et al. Cell Rep (2025) 44:116679-116679. DOI 10.1016/j.celrep.2025.116679 · PubMed

Other PDB entries of the same protein (UniProt P55899 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6C98 1.85 Å, Crystal structure of FcRn bound to UCB-84
6QIO 1.95 Å, Ternary complex of FcRn ectodomain, FcRn binding optimised human serum albumin and the…
6C97 2.0 Å, Crystal structure of FcRn at pH3
6C99 2.0 Å, Crystal structure of FcRn bound to UCB-303
9TF0 2.26 Å, Structure of echovirus 18 in complex with neonatal Fc receptor
6NHA 2.38 Å, Crystal structure of SYNT001, a human FcRn blocking monoclonal antibody
6LA6 2.39 Å, Cryo-EM structure of echovirus 11 complexed with its uncoating receptor FcRn at pH 7.4
4K71 2.4 Å, Crystal structure of a high affinity Human Serum Albumin variant bound to the Neonatal…
6WNA 2.4 Å, Next generation monomeric IgG4 Fc
9MI6 2.41 Å, Crystal structure of human FcRn in complex with nipocalimab Fab fragment
6QIP 2.45 Å, Ternary complex of FcRn ectodomain, FcRn binding optimised human serum albumin and the…
6WOL 2.49 Å, Next generation monomeric IgG4 Fc bound to neonatal Fc receptor

Browse structure collections

About this viewer

MolViewer shows 9OC6 directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.