9ISI: Human C3aR in apo state

Structure of human C3aR in apo state. Determined by electron microscopy at 3.56 Å resolution. Released 23 Apr 2025.

Method: Electron microscopy
Resolution: 3.56 Å
Organisms: Homo sapiens, Escherichia coli
Chains: 1
Atoms: 2,804
Mol. weight: 68.61 kDa
Released: 23 Apr 2025

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

Secondary structure: helices and β-sheets

9ISI contains 18 α-helices and 0 β-strands across 1 chain. 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 B: 18 helices, 0 β-strands

Element	Residues	Length
α-helix	23-35	13
α-helix	38-49	12
α-helix	58-72	15
α-helix	75-84	10
α-helix	93-96	4
α-helix	100-123	24
α-helix	127-129	3
α-helix	136-152	17
α-helix	155-158	4
α-helix	332-341	10
α-helix	342-346	5
α-helix	347-1024	43
α-helix	1028-1047	20
α-helix	1061-1085	25
α-helix	1090-1097	8
α-helix	1099-402	53
α-helix	408-437	30
α-helix	450-458	9

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
C3a anaphylatoxin chemotactic receptor,Soluble cytochrome b562	B	protein	613	Homo sapiens, Escherichia coli	P0ABE7 (AlphaFold model), Q16581 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>9ISI_1 C3a anaphylatoxin chemotactic receptor,Soluble cytochrome b562 (chains B)
DYKDDDDAIDASFSAETNSTDLLSQPWNEPPVILSMVILSLTFLLGLPGNGLVLWVAGLK
MQRTVNTIWFLHLTLADLLCCLSLPFSLAHLALQGQWPYGRFLCKLIPSIIVLNMFASVF
LLTAISLDRCLVVFKPIWCQNHRNVGMACSICGCIWVVAFVMCIPVFVYREIFTTDNHNR
CGYKFGLSSSLDYPDFYGDPLENRSLENIVQPPGEMNDRLDPSSFQTNDHPWTVPTVFQP
QTFQRPSADSLPRGSARLTSQNLYSNVFKPADVVSPKIPSGFPIEDHETSPLDNSDAFLS
THLKLFPSASSNSFYESELPQGFQDYYNLGQFTDDDQVPTPLVAITITRLVVGFLLPSVI
MIACYSFIVFRMQRARRQLADLEDNWETLNDNLKVIEKADNAAQVKDALTKMRAAALDAQ
KATPPKLEDKSPDSPEMKDFRHGFDILVGQIDDALKLANEGKVKEAQAAAEQLKTTRNAY
IQKYLERARSTLKSQSKTFRVAVVVVAVFLVCWTPYHIFGVLSLLTDPETPLGKTLMSWD
HVCIALASANSCFNPFLYALLGKDFRKKARQSIQGILEAAFSEELTRSTHCPSNNVISER
NSTTVASLEVLFQ

Primary citation

Structural insights into small-molecule agonist recognition and activation of complement receptor C3aR. Kim, J., Ko, S., Choi, C. et al. EMBO J (2025) 44:2803-2826. DOI 10.1038/s44318-025-00429-w · PubMed

Other PDB entries of the same protein (UniProt P0ABE7 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6DYF 1.1 Å, Cu(II)-bound structure of the engineered cyt cb562 variant, CH3Y
5YO6 1.2 Å, Crystal Structure of B562RIL with engineered disulfide bond T9C-A36C
4JEA 1.22 Å, Crystal structure of an engineered Zn-RIDC1 construct with four interfacial disulfide…
7LSJ 1.26 Å, Cu-bound crystal structure of the engineered cyt cb562 variant, DiCyt2 - H63A,…
7MK4 1.27 Å, Co-bound crystal structure of the engineered cyt cb562 variant, DiCyt2
6DYC 1.33 Å, Co(II)-bound structure of the engineered cyt cb562 variant, CH3
5YO4 1.37 Å, Crystal Structure of B562RIL with engineered disulfide bond K27C-A79C
256B 1.4 Å, Improvement of the 2.5 Å resolution model of cytochrome B562 by redetermining the…
6OT4 1.4 Å, Bimetallic dodecameric cage design 2 (BMC2) from cytochrome cb562
7LRV 1.4 Å, Ni-bound crystal structure of the engineered cyt cb562 variant, DiCyt2, crystallized in…
9PQ4 1.48 Å, Bi-bound structure of the H77C variant of TriCyt2
6DYG 1.49 Å, Fe(II)-bound structure of the engineered cyt cb562 variant, CH3Y

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