9SPA: Apo ACE2 extracellular domain

Apo ACE2 extracellular domain. Determined by X-ray diffraction at 1.79 Å resolution. Released 8 Apr 2026.

Method: X-ray diffraction
Resolution: 1.79 Å
Organism: Homo sapiens
Chains: 1
Atoms: 5,310
Mol. weight: 70.76 kDa
Ligands: ZN, MLA
Released: 8 Apr 2026

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

Secondary structure: helices and β-sheets

9SPA contains 38 α-helices and 11 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 C: 38 helices, 11 β-strands

Element	Residues	Length	Sheet
α-helix	3-34	32
α-helix	38-63	26
α-helix	67-69	3
α-helix	73-83	11
α-helix	92-111	20
β-strand	113-115	3	1
β-strand	123-125	3	1
α-helix	126-130	5
α-helix	131-136	6
α-helix	140-149	10
α-helix	150-155	6
α-helix	156-175	20
α-helix	181-186	6
α-helix	187-189	3
β-strand	191	1	2
β-strand	199	1	2
α-helix	201-233	33
β-strand	242	1	3
α-helix	243	1
β-strand	244-245	2	4
α-helix	258-260	3
α-helix	261-264	4
α-helix	271-272	2
α-helix	276-281	6
α-helix	286-299	14
α-helix	302-306	5
α-helix	307-312	6
β-strand	314	1	5
β-strand	329-332	4	5
β-strand	338-341	4	5
α-helix	348-366	19
α-helix	372-374	3
α-helix	380-394	15
α-helix	397-402	6
α-helix	414-428	15
α-helix	431-446	16
α-helix	452-454	3
α-helix	455-462	8
α-helix	463-467	5
β-strand	469-470	2	4
α-helix	481-484	4
α-helix	486-489	4
α-helix	496-514	19
α-helix	521-523	3
α-helix	530-540	11
α-helix	548-556	9
α-helix	564-580	17
α-helix	581-583	3
β-strand	589	1	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Processed angiotensin-converting enzyme 2	C	protein	609	Homo sapiens	Q9BYF1 (AlphaFold model)

Sequence of entity 1 (C), FASTA

>9SPA_1 Processed angiotensin-converting enzyme 2 (chains C)
GSTIEEQAKTFLDKFNHEAEDLFYQSSLASWNYNTNITEENVQNMNNAGDKWSAFLKEQS
TLAQMYPLQEIQNLTVKLQLQALQQNGSSVLSEDKSKRLNTILNTMSTIYSTGKVCNPDN
PQECLLLEPGLNEIMANSLDYNERLWAWESWRSEVGKQLRPLYEEYVVLKNEMARANHYE
DYGDYWRGDYEVNGVDGYDYSRGQLIEDVEHTFEEIKPLYEHLHAYVRAKLMNAYPSYIS
PIGCLPAHLLGDMWGRFWTNLYSLTVPFGQKPNIDVTDAMVDQAWDAQRIFKEAEKFFVS
VGLPNMTQGFWENSMLTDPGNVQKAVCHPTAWDLGKGDFRILMCTKVTMDDFLTAHHEMG
HIQYDMAYAAQPFLLRNGANEGFHEAVGEIMSLSAATPKHLKSIGLLSPDFQEDNETEIN
FLLKQALTIVGTLPFTYMLEKWRWMVFKGEIPKDQWMKKWWEMKREIVGVVEPVPHDETY
CDPASLFHVSNDYSFIRYYTRTLYQFQFQEALCQAAKHEGPLHKCDISNSTEAGQKLFNM
LRLGKSEPWTLALENVVGAKNMNVRPLLNYFEPLFTWLKDQNKNSFVGWSTDWSPYADSS
PHHHHHHHH

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	1
MLA	Malonic acid	C3 H4 O4	1

Primary citation

Yeast Display Technology Enables Rapid Discovery of Low-Nanomolar Macrocyclic Peptide Inhibitors of Human Angiotensin-Converting Enzyme 2. Romanyuk, Z., Bettin, G., Brear, P. et al. J Med Chem (2026) 69:7689-7708. DOI 10.1021/acs.jmedchem.5c02876 · PubMed

Other PDB entries of the same protein (UniProt Q9BYF1 (AlphaFold model), which also has an AlphaFold model), best resolution first:

28KD 2.02 Å, ACE2 extracellular domain in complex with the macrocyclic peptide GR3.1.2
8BYJ 2.07 Å, The structures of Ace2 in complex with bicyclic peptide inhibitor
8B9P 2.11 Å, ACE2 in complex with bicyclic peptide inhibitor
8XSF 2.16 Å, SARS-CoV-2 rbd + imcas-364 + hACE2
1R42 2.2 Å, Native Human Angiotensin Converting Enzyme-Related Carboxypeptidase (ACE2)
7JVO 2.2 Å, Importin alpha bound to the C-terminus of ACE2
8TOR 2.2 Å, ACE2-peptide 2 complex
9RVA 2.2 Å, Crystal structure of the extracellular part of human ACE2 in complex with the…
9UE7 2.27 Å, Cryo-EM structure of SARS-CoV-2 KP.2 spike in complex with ACE2
8TOQ 2.3 Å, ACE2-peptide 1 complex
8BFW 2.33 Å, The structures of Ace2 in complex with bicyclic peptide inhibitor
8TOS 2.35 Å, ACE2-peptide 6 complex

Browse structure collections

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