9GNS | pdb_00009gns

X-ray structure of Human holo aromatic L-amino acid decarboxylase (AADC) complex with Carbidopa at physiological pH


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.93 Å
  • R-Value Free: 
    0.192 (Depositor), 0.197 (DCC) 
  • R-Value Work: 
    0.174 (Depositor) 
  • R-Value Observed: 
    0.175 (Depositor) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history

Literature

alpha-Hydrazino Acids Inhibit Pyridoxal Phosphate-Dependent Decarboxylases via "Catalytically Correct" Ketoenamine Tautomers: A Special Motif for Chemical Biology and Drug Discovery?

Baine, J.M.Duhoo, Y.Doukov, T.Desfosses, A.Bisello, G.Beio, M.L.Bauer, O.Perduca, M.Bacia-Verloop, M.Bertoldi, M.Phillips, R.S.Gutsche, I.Berkowitz, D.B.

(2025) ACS Catal 15: 8204-8218

  • DOI: https://doi.org/10.1021/acscatal.5c00326
  • Primary Citation Related Structures: 
    9DUI, 9E0M, 9E0O, 9E0Q, 9GNS

  • PubMed Abstract: 

    We present evidence that supports a 'correct hydrazone tautomer/Dunathan alignment model' for how α-hydrazino analogues of α-amino acids inhibit PLP enzymes. Described is the asymmetric synthesis of l- and d-α-hydrazino acid l-lysine analogues and their inhibition of Hafnia alvei lysine decarboxylase (LdcI) via kinetic analysis, stopped-flow spectrophotometry, and cryo-EM. We describe a similar investigation of the important anti-Parkinsonism drug, carbidopa, with its human DOPA decarboxylase (hDdc) target. Evidence is consistent with these three hydrazino analogues forming the catalytically relevant ketoenamine PLP-hydrazone tautomer in their target active sites, with the α-carboxylate groups, though insulated, aligning with the PLP-π-system in a Dunathan-model-like orientation. High-resolution cryo-EM structures of the H. alvei LdcI holoenzyme (pdb 9E0M-2.1Å) and LdcI-bound l- and d-hydrazones (pdb 9E0O-2.0 Å; pdb 9E0Q-2.3Å) and the first X-ray crystal structure of hDdc-bound carbidopa (pdb 9GNS-1.93Å) support this 'correct tautomer' model. These insights are expected to guide future PLP enzyme inhibitor development.


  • Organizational Affiliation
    • Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States.

Macromolecule Content 

  • Total Structure Weight: 54.63 kDa 
  • Atom Count: 3,933 
  • Modeled Residue Count: 465 
  • Deposited Residue Count: 480 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Aromatic-L-amino-acid decarboxylase480Homo sapiensMutation(s): 0 
Gene Names: DDChCG_1811384tcag7.584
EC: 4.1.1.28
UniProt & NIH Common Fund Data Resources
Find proteins for P20711 (Homo sapiens)
Explore P20711 
Go to UniProtKB:  P20711
PHAROS:  P20711
GTEx:  ENSG00000132437 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP20711
Sequence Annotations
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Reference Sequence

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.93 Å
  • R-Value Free:  0.192 (Depositor), 0.197 (DCC) 
  • R-Value Work:  0.174 (Depositor) 
  • R-Value Observed: 0.175 (Depositor) 
Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.921α = 90
b = 106.921β = 90
c = 219.752γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
FFTphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Other private--

Revision History  (Full details and data files)

  • Version 1.0: 2025-05-14
    Type: Initial release
  • Version 1.1: 2025-06-04
    Changes: Database references