22CR: C5a-desArg bound C5aR2

C5a-desArg bound C5aR2 in complex with beta-arrestin1. Determined by electron microscopy at 2.9 Å resolution. Released 22 Jul 2026.

Method: Electron microscopy
Resolution: 2.9 Å
Organisms: Homo sapiens, Mus musculus, Bos taurus
Chains: 5
Atoms: 7,071
Mol. weight: 136.83 kDa
Released: 22 Jul 2026

Explore 22CR in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

22CR contains 33 α-helices and 54 β-strands across 5 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: 10 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	7-8	2	3
β-strand	9-12	4	8
β-strand	18-22	5	8
β-strand	26-28	3	9
β-strand	29	1	10
β-strand	34	1	10
α-helix	35-36	2
β-strand	37-43	7	8
β-strand	52-62	11	11
α-helix	69-71	3
β-strand	76-87	12	11
α-helix	91-93	3
α-helix	99-107	9
β-strand	112-117	6	8
α-helix	124-126	3
β-strand	127-129	3	11
α-helix	139-140	2
β-strand	141-151	11	11
α-helix	157-159	3
α-helix	160-162	3
β-strand	163-168	6	11
β-strand	169-171	3	9
β-strand	183-190	8	12
β-strand	193-203	11	12
β-strand	207-208	2	13
β-strand	214-222	9	12
α-helix	227	1
β-strand	228-241	14	14
β-strand	249-258	10	14
β-strand	262	1	14
β-strand	266-274	9	12
β-strand	288-290	3	11
β-strand	300	1	11
α-helix	302-307	6
β-strand	317-329	13	14
β-strand	342-349	8	14
β-strand	350-351	2	13

Chain C: 5 helices, 0 β-strands

Element	Residues	Length
α-helix	5-8	4
α-helix	17-20	4
α-helix	22-26	5
α-helix	33-35	3
α-helix	47-61	15

Chain H: 2 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	6-10	5	4
β-strand	13-14	2	5
β-strand	21-28	8	4
β-strand	35-42	8	5
β-strand	49-55	7	5
β-strand	60-63	4	5
α-helix	65-67	3
β-strand	71-76	6	4
β-strand	81-86	6	4
α-helix	91-93	3
β-strand	95-103	9	5
β-strand	112-113	2	5
β-strand	117-120	4	5

Chain L: 2 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	5-8	4	6
β-strand	11-13	3	7
β-strand	20-26	7	6
β-strand	34-39	6	7
α-helix	44-45	2
β-strand	46-50	5	7
β-strand	54-55	2	7
β-strand	63-68	6	6
β-strand	71-76	6	6
β-strand	86-91	6	7
α-helix	97	1
β-strand	98-99	2	7
β-strand	103-106	4	7

Chain R: 14 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	33-36	4
α-helix	38-59	22
β-strand	63	1	1
β-strand	67	1	1
α-helix	73-96	24
α-helix	104-133	30
α-helix	135-137	3
α-helix	154-164	11
α-helix	167-170	4
β-strand	173-179	7	2
β-strand	182-188	7	2
α-helix	194-207	14
α-helix	212-226	15
α-helix	232-235	4
α-helix	238-258	21
α-helix	264-281	18
α-helix	283-294	12
α-helix	295-298	4
β-strand	327-328	2	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
C5a anaphylatoxin	C	protein	74	Homo sapiens	P01031 (AlphaFold model)
C5a anaphylatoxin chemotactic receptor 2	R	protein	337	Homo sapiens	Q9P296 (AlphaFold model)
Fab30 heavy chain	H	protein	229	Mus musculus
Fab30 light chain	L	protein	215	Mus musculus
Beta-arrestin-1	A	protein	393	Bos taurus	P17870 (AlphaFold model)

Sequence of entity 1 (C), FASTA

>22CR_1 C5a anaphylatoxin (chains C)
TLQKKIEEIAAKYKHSVVKKCCYDGARVNNDETCEQRAARISLGPRCIKAFTECCVVASQ
LRANISHKDMQLGR

Sequence of entity 2 (R), FASTA

>22CR_2 C5a anaphylatoxin chemotactic receptor 2 (chains R)
MGNDSVSYEYGDYSDLSDRPVDCLDGACLAIDPLRVAPLPLYAAIFLVGVPGNAMVAWVA
GKVARRRVGATWLLHLAVADLLCCLSLPILAVPIARGGHWPYGAVGCRALPSIILLTMYA
SVLLLAALSADLCFLALGPAWWSTVQRACGVQVACGAAWTLALLLTVPSAIYRRLHQEHF
PARLQCVVDYGGSSSTENAVTAIRFLFGFLGPLVAVASCHSALLCWAARRCRPLGTAIVV
GFFVCWAPYHLLGLVLTVAAPNSALLARALRAEPLIVGLALAHSCLNPMLFLYFGRAQLR
RSLPAACHWALRESQGQDESVDSKKSTSHDLVSEMEV

Sequence of entity 3 (H), FASTA

>22CR_3 Fab30 heavy chain (chains H)
EISEVQLVESGGGLVQPGGSLRLSCAASGFNVYSSSIHWVRQAPGKGLEWVASISSYYGY
TYYADSVKGRFTISADTSKNTAYLQMNSLRAEDTAVYYCARSRQFWYSGLDYWGQGTLVT
VSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVL
QSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKT

Sequence of entity 4 (L), FASTA

>22CR_4 Fab30 light chain (chains L)
SDIQMTQSPSSLSASVGDRVTITCRASQSVSSAVAWYQQKPGKAPKLLIYSASSLYSGVP
SRFSGSRSGTDFTLTISSLQPEDFATYYCQQYKYVPVTFGQGTKVEIKRTVAAPSVFIFP
PSDSQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTL
TLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

Sequence of entity 5 (A), FASTA

>22CR_5 Beta-arrestin-1 (chains A)
MGDKGTRVFKKASPNGKLTVYLGKRDFVDHIDLVEPVDGVVLVDPEYLKERRVYVTLTCA
FRYGREDLDVLGLTFRKDLFVANVQSFPPAPEDKKPLTRLQERLIKKLGEHAYPFTFEIP
PNLPCSVTLQPGPEDTGKACGVDYEVKAFCAENLEEKIHKRNSVRLVIEKVQYAPERPGP
QPTAETTRQFLMSDKPLHLEASLDKEIYYHGEPISVNVHVTNNTNKTVKKIKISVRQYAD
ICLFNTAQYKCPVAMEEADDTVAPSSTFCKVYTLTPFLANNREKRGLALDGKLKHEDTNL
ASSTLLREGANREILGIIVSYKVKVKLVVSRGGLLGDLASSDVAVELPFTLMHPKPKEEP
PHREVPEHETPVDTNLIELDTNDDDAAAEDFAR

Primary citation

Atypical signaling, ligand recognition and selective agonist discovery of complement receptor C5aR2. Qin, J., Cai, C., Shan, M. et al. Cell Res (2026) 36:718-733. DOI 10.1038/s41422-026-01273-1 · PubMed

Other PDB entries of the same protein (UniProt P01031 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9Y6C 2.0 Å, X-ray structure analysis of human Complement Component 5 TE domain in complex with the…
5B71 2.11 Å, Crystal structure of complement C5 in complex with SKY59
4UU9 2.12 Å, Crystal structure of the human c5a in complex with MEDI7814 a neutralising antibody
7AD7 2.3 Å, Crystal structure of human complement C5 in complex with the K8 bovine knob domain…
5B4P 2.4 Å, Complex structure of human C5a and its binding repebody
4P39 2.4 Å, Crystal structure of the human C5aR antagonist C5a-A8
7OP0 2.57 Å, Crystal structure of complement C5 in complex with chemically synthesized K92 knob domain.
3HQA 2.59 Å, Crystal structure of human desarg-C5A
5HCC 2.59 Å, Ternary complex of human Complement C5 with Ornithodoros moubata OmCI and Dermacentor…
22GM 2.7 Å, C5a bound C5aR1 in complex with beta-arrestin1
6RPT 2.7 Å, Structure of tick complement inhibitor CirpT1 complexed with macroglobubulin domain 4 of…
7AD6 2.75 Å, Crystal structure of human complement C5 in complex with the K92 bovine knob domain…

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