Ornithine aminotransferase inactivated by (1R,3S,4S)-3-amino-4-fluorocyclopentane-1-carboxylic acid (FCP)

Experimental Data Snapshot

  • Resolution: 1.77 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 

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This is version 1.5 of the entry. See complete history


Selective Targeting by a Mechanism-Based Inactivator against Pyridoxal 5'-Phosphate-Dependent Enzymes: Mechanisms of Inactivation and Alternative Turnover.

Mascarenhas, R.Le, H.V.Clevenger, K.D.Lehrer, H.J.Ringe, D.Kelleher, N.L.Silverman, R.B.Liu, D.

(2017) Biochemistry 56: 4951-4961

  • DOI: https://doi.org/10.1021/acs.biochem.7b00499
  • Primary Citation of Related Structures:  
    5VWO, 5VWQ, 5VWR

  • PubMed Abstract: 

    Potent mechanism-based inactivators can be rationally designed against pyridoxal 5'-phosphate (PLP)-dependent drug targets, such as ornithine aminotransferase (OAT) or γ-aminobutyric acid aminotransferase (GABA-AT). An important challenge, however, is the lack of selectivity toward other PLP-dependent, off-target enzymes, because of similarities in mechanisms of all PLP-dependent aminotransferase reactions. On the basis of complex crystal structures, we investigate the inactivation mechanism of OAT, a hepatocellular carcinoma target, by (1R,3S,4S)-3-amino-4-fluorocyclopentane-1-carboxylic acid (FCP), a known inactivator of GABA-AT. A crystal structure of OAT and FCP showed the formation of a ternary adduct. This adduct can be rationalized as occurring via an enamine mechanism of inactivation, similar to that reported for GABA-AT. However, the crystal structure of an off-target, PLP-dependent enzyme, aspartate aminotransferase (Asp-AT), in complex with FCP, along with the results of attempted inhibition assays, suggests that FCP is not an inactivator of Asp-AT, but rather an alternate substrate. Turnover of FCP by Asp-AT is also supported by high-resolution mass spectrometry. Amid existing difficulties in achieving selectivity of inactivation among a large number of PLP-dependent enzymes, the obtained results provide evidence that a desirable selectivity could be achieved, taking advantage of subtle structural and mechanistic differences between a drug-target enzyme and an off-target enzyme, despite their largely similar substrate binding sites and catalytic mechanisms.

  • Organizational Affiliation

    Department of Chemistry and Biochemistry, Loyola University Chicago , Chicago, Illinois 60660, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ornithine aminotransferase, mitochondrial
A, B, C
404Homo sapiensMutation(s): 0 
Gene Names: OAT
UniProt & NIH Common Fund Data Resources
Find proteins for P04181 (Homo sapiens)
Explore P04181 
Go to UniProtKB:  P04181
PHAROS:  P04181
GTEx:  ENSG00000065154 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04181
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 9QJ

Download Ideal Coordinates CCD File 
D [auth A],
E [auth B],
F [auth C]
(1S,3S,4E)-3-({3-hydroxy-2-methyl-5-[(phosphonooxy)methyl]pyridin-4-yl}methyl)-4-iminocyclopentane-1-carboxylic acid
C14 H19 N2 O7 P
Experimental Data & Validation

Experimental Data

  • Resolution: 1.77 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 115.305α = 90
b = 115.305β = 90
c = 187.991γ = 120
Software Package:
Software NamePurpose
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute on Drug Abuse (NIH/NIDA)United StatesR01 DA030604

Revision History  (Full details and data files)

  • Version 1.0: 2017-08-30
    Type: Initial release
  • Version 1.1: 2017-09-20
    Changes: Database references
  • Version 1.2: 2017-09-27
    Changes: Author supporting evidence
  • Version 1.3: 2017-10-04
    Changes: Database references
  • Version 1.4: 2019-12-11
    Changes: Author supporting evidence
  • Version 1.5: 2023-10-04
    Changes: Data collection, Database references, Refinement description