28KD: ACE2 extracellular domain

ACE2 extracellular domain in complex with the macrocyclic peptide GR3.1.2. Determined by X-ray diffraction at 2.02 Å resolution. Released 8 Apr 2026.

Method: X-ray diffraction
Resolution: 2.02 Å
Organisms: Homo sapiens, Synthetic plasmid
Chains: 4
Atoms: 10,621
Mol. weight: 145.68 kDa
Ligands: ZN
Released: 8 Apr 2026

Explore 28KD in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

28KD contains 85 α-helices and 18 β-strands across 4 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: 41 helices, 9 β-strands

Element	Residues	Length	Sheet
α-helix	20-52	33
α-helix	56-80	25
α-helix	85-87	3
α-helix	91-100	10
α-helix	105-107	3
α-helix	110-129	20
β-strand	131-134	4	5
β-strand	137-143	7	5
α-helix	144-148	5
α-helix	149-154	6
α-helix	158-167	10
α-helix	168-173	6
α-helix	174-193	20
α-helix	199-204	6
α-helix	205-207	3
β-strand	209	1	6
β-strand	217	1	6
α-helix	219-251	33
α-helix	261	1
β-strand	262-263	2	7
α-helix	264-266	3
α-helix	276-278	3
α-helix	279-282	4
α-helix	289-290	2
α-helix	294-299	6
α-helix	304-317	14
α-helix	320-324	5
α-helix	325-330	6
β-strand	332	1	8
β-strand	347-352	6	8
β-strand	355-359	5	8
α-helix	366-384	19
α-helix	390-392	3
α-helix	400-412	13
α-helix	415-420	6
α-helix	432-446	15
α-helix	449-465	17
α-helix	470-472	3
α-helix	473-480	8
α-helix	481-485	5
β-strand	487-488	2	7
α-helix	499-502	4
α-helix	504-507	4
α-helix	514-532	19
α-helix	539-541	3
α-helix	548-558	11
α-helix	566-574	9
α-helix	582-587	6
α-helix	589-599	11
α-helix	603-604	2

Chain B: 40 helices, 9 β-strands

Element	Residues	Length	Sheet
α-helix	21-52	32
α-helix	56-79	24
α-helix	80-82	3
α-helix	85-87	3
α-helix	91-100	10
α-helix	105-107	3
α-helix	110-129	20
β-strand	131-133	3	1
β-strand	141-143	3	1
α-helix	144-148	5
α-helix	149-154	6
α-helix	158-167	10
α-helix	168-173	6
α-helix	174-193	20
α-helix	199-204	6
α-helix	205-207	3
β-strand	209	1	2
β-strand	217	1	2
α-helix	219-251	33
α-helix	261	1
β-strand	262-263	2	3
α-helix	276-278	3
α-helix	279-282	4
α-helix	289-290	2
α-helix	294-299	6
α-helix	304-317	14
α-helix	320-324	5
α-helix	325-330	6
β-strand	332	1	4
β-strand	347-352	6	4
β-strand	355-359	5	4
α-helix	366-384	19
α-helix	385-387	3
α-helix	390-392	3
α-helix	400-412	13
α-helix	415-420	6
α-helix	432-446	15
α-helix	449-465	17
α-helix	470-472	3
α-helix	473-480	8
α-helix	481-485	5
β-strand	487-488	2	3
α-helix	499-502	4
α-helix	504-507	4
α-helix	514-532	19
α-helix	539-541	3
α-helix	548-558	11
α-helix	566-574	9
α-helix	582-599	18

Chain C: 2 helices, 0 β-strands

Element	Residues	Length	Sheet
α-helix	366-369	4
α-helix	373-377	5

Chain D: 2 helices, 0 β-strands

Element	Residues	Length	Sheet
α-helix	366-369	4
α-helix	373-378	6

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Processed angiotensin-converting enzyme 2	A, B	protein	609	Homo sapiens	Q9BYF1 (AlphaFold model)
Ala-cys-phe-leu-arg-cys-his-arg-asp-val-lys-cys-trp-leu-trp-cys-ser-gly	C, D	protein	18	Synthetic plasmid

Sequence of entity 1 (A, B), FASTA

>28KD_1 Processed angiotensin-converting enzyme 2 (chains A, B)
GSTIEEQAKTFLDKFNHEAEDLFYQSSLASWNYNTNITEENVQNMNNAGDKWSAFLKEQS
TLAQMYPLQEIQNLTVKLQLQALQQNGSSVLSEDKSKRLNTILNTMSTIYSTGKVCNPDN
PQECLLLEPGLNEIMANSLDYNERLWAWESWRSEVGKQLRPLYEEYVVLKNEMARANHYE
DYGDYWRGDYEVNGVDGYDYSRGQLIEDVEHTFEEIKPLYEHLHAYVRAKLMNAYPSYIS
PIGCLPAHLLGDMWGRFWTNLYSLTVPFGQKPNIDVTDAMVDQAWDAQRIFKEAEKFFVS
VGLPNMTQGFWENSMLTDPGNVQKAVCHPTAWDLGKGDFRILMCTKVTMDDFLTAHHEMG
HIQYDMAYAAQPFLLRNGANEGFHEAVGEIMSLSAATPKHLKSIGLLSPDFQEDNETEIN
FLLKQALTIVGTLPFTYMLEKWRWMVFKGEIPKDQWMKKWWEMKREIVGVVEPVPHDETY
CDPASLFHVSNDYSFIRYYTRTLYQFQFQEALCQAAKHEGPLHKCDISNSTEAGQKLFNM
LRLGKSEPWTLALENVVGAKNMNVRPLLNYFEPLFTWLKDQNKNSFVGWSTDWSPYADSS
PHHHHHHHH

Sequence of entity 2 (C, D), FASTA

>28KD_2 ALA-CYS-PHE-LEU-ARG-CYS-HIS-ARG-ASP-VAL-LYS-CYS-TRP-LEU-TRP-CYS-SER-GLY (chains C, D)
ACFLRCHRDVKCWLWCSG

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	2

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:

9SPA 1.79 Å, Apo ACE2 extracellular domain
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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