6CIC

Structure of the human nitric oxide synthase R354A/G357D mutant heme domain in complex with N-(1-(2-(Ethyl(methyl)amino)ethyl)-1,2,3,4-tetrahydroquino-lin-6-yl)thiophene-2-carboximidamide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history

Re-refinement Note

A newer entry is available that reflects an alternative modeling of the original data: 6CIC


Literature

Structural Basis for Isoform Selective Nitric Oxide Synthase Inhibition by Thiophene-2-carboximidamides.

Li, H.Evenson, R.J.Chreifi, G.Silverman, R.B.Poulos, T.L.

(2018) Biochemistry 57: 6319-6325

  • DOI: https://doi.org/10.1021/acs.biochem.8b00895
  • Primary Citation of Related Structures:  
    6CIC, 6CID, 6CIE, 6CIF

  • PubMed Abstract: 

    The overproduction of nitric oxide in the brain by neuronal nitric oxide synthase (nNOS) is associated with a number of neurodegenerative diseases. Although inhibiting nNOS is an important therapeutic goal, it is important not to inhibit endothelial NOS (eNOS) because of the critical role played by eNOS in maintaining vascular tone. While it has been possible to develop nNOS selective aminopyridine inhibitors, many of the most potent and selective inhibitors exhibit poor bioavailability properties. Our group and others have turned to more biocompatible thiophene-2-carboximidamide (T2C) inhibitors as potential nNOS selective inhibitors. We have used crystallography and computational methods to better understand how and why two commercially developed T2C inhibitors exhibit selectivity for human nNOS over human eNOS. As with many of the aminopyridine inhibitors, a critical active site Asp residue in nNOS versus Asn in eNOS is largely responsible for controlling selectivity. We also present thermodynamic integration results to better understand the change in p K a and thus the charge of inhibitors once bound to the active site. In addition, relative free energy calculations underscore the importance of enhanced electrostatic stabilization of inhibitors bound to the nNOS active site compared to eNOS.


  • Organizational Affiliation

    Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry , University of California , Irvine , California 92697-3900 , United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitric oxide synthase, brain
A, B
421Homo sapiensMutation(s): 2 
Gene Names: NOS1
EC: 1.14.13.39
UniProt & NIH Common Fund Data Resources
Find proteins for P29475 (Homo sapiens)
Explore P29475 
Go to UniProtKB:  P29475
PHAROS:  P29475
GTEx:  ENSG00000089250 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29475
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download Ideal Coordinates CCD File 
C [auth A],
H [auth B]
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
7R2
Query on 7R2

Download Ideal Coordinates CCD File 
E [auth A],
J [auth B]
N-(1-{2-[ethyl(methyl)amino]ethyl}-1,2,3,4-tetrahydroquinolin-6-yl)thiophene-2-carboximidamide
C19 H26 N4 S
GDMWZTBOBNMXTL-UHFFFAOYSA-N
H4B
Query on H4B

Download Ideal Coordinates CCD File 
D [auth A],
I [auth B]
5,6,7,8-TETRAHYDROBIOPTERIN
C9 H15 N5 O3
FNKQXYHWGSIFBK-RPDRRWSUSA-N
GOL
Query on GOL

Download Ideal Coordinates CCD File 
F [auth A],
K [auth B]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
ZN
Query on ZN

Download Ideal Coordinates CCD File 
G [auth A]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
Binding Affinity Annotations 
IDSourceBinding Affinity
7R2 BindingDB:  6CIC IC50: 97 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.318α = 90
b = 122.157β = 90
c = 165.131γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
REFMACphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Cancer Institute (NIH/NCI)United StatesGM57353

Revision History  (Full details and data files)

  • Version 1.0: 2018-10-31
    Type: Initial release
  • Version 1.1: 2018-11-07
    Changes: Data collection, Database references
  • Version 1.2: 2018-11-21
    Changes: Data collection, Database references
  • Version 1.3: 2019-12-04
    Changes: Author supporting evidence
  • Version 1.4: 2023-10-04
    Changes: Data collection, Database references, Derived calculations, Refinement description