9SS9 | pdb_00009ss9

Human angiotensin 1-converting enzyme N-domain in complex with captopril


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 
    0.227 (Depositor), 0.233 (DCC) 
  • R-Value Work: 
    0.185 (Depositor), 0.193 (DCC) 

Starting Model: experimental
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Literature

Kinetic and structural characterisation of domain-specific angiotensin I-converting enzyme inhibition by captopril, rentiapril and zofenoprilat.

Gregory, K.S.Ramasamy, V.Sturrock, E.D.Acharya, K.R.

(2026) FEBS J 

  • DOI: https://doi.org/10.1111/febs.70428
  • Primary Citation of Related Structures:  
    9SS7, 9SS8, 9SS9, 9SSA, 9SSB

  • PubMed Abstract: 

    Angiotensin I-converting enzyme (ACE) is a zinc-dependent dipeptidyl carboxypeptidase involved in blood pressure regulation through proteolysis of angiotensin I (Ang-I) into the potent vasoconstrictor, angiotensin II (Ang-II). Inhibition of ACE is therefore used for the treatment of hypertension, heart failure, myocardial infarction, stroke and chronic kidney disease. Current ACE inhibitors (ACEi) bind both the N- and C-catalytic domains of ACE (referred to as nACE and cACE), and this has been linked to the occurrence of side effects due to the wide substrate specificity of ACE. The development of domain selective ACEi with reduced side effects is therefore key for improved therapeutic intervention. Understanding how current ACEi bind nACE and cACE, and their differences in domain selectivity should aid structure-based development of more selective ACEi by identifying different chemical groups that increase or decrease selectivity. We present the kinetic and structural characterisation of nACE and cACE with three thiolate ACEi, captopril (K i , nACE = 2.53 nm and cACE = 2.04 nm), rentiapril (monomer K i , nACE = 2.22 nm and cACE = 6.77 nm) and zofenoprilat (K i , nACE = 2.86 nm and cACE = 0.61 nm). Detailed structural analysis indicated that the S2' subsite likely contributes to the variation in domain selectivity observed for rentiapril and zofenoprilat due to differences in hydrophobicity and displacement of water molecules that contribute to ACE's hydration shell. Interestingly, in the cACE crystal structure, rentiapril bound as a dimer, and kinetic data revealed that both the monomeric and dimeric (dimer K i , nACE = 15.11 nm and cACE = 36.38 nm) forms of rentiapril inhibit ACE with nanomolar affinity.


  • Organizational Affiliation
    • Department of Life Sciences, University of Bath, UK.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Angiotensin-converting enzyme, soluble formA [auth B],
B [auth A]
628Homo sapiensMutation(s): 0 
Gene Names: ACEDCPDCP1
EC: 3.4.15.1
UniProt & NIH Common Fund Data Resources
Find proteins for P12821 (Homo sapiens)
Explore P12821 
Go to UniProtKB:  P12821
PHAROS:  P12821
GTEx:  ENSG00000159640 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12821
Glycosylation
Glycosylation Sites: 3Go to GlyGen: P12821-1
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
C, D
2N-Glycosylation
Small Molecules
Ligands 10 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download Ideal Coordinates CCD File 
M [auth B],
O [auth A],
P [auth A],
Y [auth A]
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
MCO (Subject of Investigation/LOI)
Query on MCO

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R [auth A]1-(3-MERCAPTO-2-METHYL-PROPIONYL)-PYRROLIDINE-2-CARBOXYLIC ACID
C9 H15 N O3 S
FAKRSMQSSFJEIM-RNFRBKRXSA-N
X8Z
Query on X8Z

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L [auth B]L-CAPTOPRIL
C9 H15 N O3 S
FAKRSMQSSFJEIM-RQJHMYQMSA-N
PG4
Query on PG4

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S [auth A],
U [auth A]
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
BCN
Query on BCN

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K [auth B]BICINE
C6 H13 N O4
FSVCELGFZIQNCK-UHFFFAOYSA-N
PGE
Query on PGE

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I [auth B],
T [auth A]
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
PEG
Query on PEG

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F [auth B],
H [auth B],
V [auth A],
W [auth A]
DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
ZN (Subject of Investigation/LOI)
Query on ZN

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E [auth B],
Q [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
EDO
Query on EDO

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G [auth B],
J [auth B],
X [auth A]
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
CL
Query on CL

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N [auth B],
Z [auth A]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free:  0.227 (Depositor), 0.233 (DCC) 
  • R-Value Work:  0.185 (Depositor), 0.193 (DCC) 
Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 72.043α = 89.305
b = 77.499β = 65.326
c = 80.628γ = 75.336
Software Package:
Software NamePurpose
REFMACrefinement
DIALSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research Council (BBSRC)United KingdomBB/X001032/1

Revision History  (Full details and data files)

  • Version 1.0: 2026-02-18
    Type: Initial release