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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Ligand Structure Quality Assessment 


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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 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.

Macromolecule Content 

  • Total Structure Weight: 148.82 kDa 
  • Atom Count: 10,160 
  • Modeled Residue Count: 1,204 
  • Deposited Residue Count: 1,256 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  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

Help  
Entity ID: 2
MoleculeChains Length2D Diagram GlycosylationD Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
C, D
2N-Glycosylation
Glycosylation Resources
GlyTouCan: G42666HT
GlyCosmos: G42666HT
GlyGen: G42666HT

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



Download:Ideal Coordinates CCD File
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



Download:Ideal Coordinates CCD File
L [auth B]L-CAPTOPRIL
C9 H15 N O3 S
FAKRSMQSSFJEIM-RQJHMYQMSA-N
PG4

Query on PG4



Download:Ideal Coordinates CCD File
S [auth A],
U [auth A]
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
BCN

Query on BCN



Download:Ideal Coordinates CCD File
K [auth B]BICINE
C6 H13 N O4
FSVCELGFZIQNCK-UHFFFAOYSA-N
PGE

Query on PGE



Download:Ideal Coordinates CCD File
I [auth B],
T [auth A]
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
PEG

Query on PEG



Download:Ideal Coordinates CCD File
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



Download:Ideal Coordinates CCD File
E [auth B],
Q [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
EDO

Query on EDO



Download:Ideal Coordinates CCD File
G [auth B],
J [auth B],
X [auth A]
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
CL

Query on CL



Download:Ideal Coordinates CCD File
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