3NQS

Crystal Structure of Inducible Nitric Oxide Synthase with N-Nitrosated-pterin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.204 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Nitric-oxide synthase forms N-NO-pterin and S-NO-cys: implications for activity, allostery, and regulation.

Rosenfeld, R.J.Bonaventura, J.Szymczyna, B.R.MacCoss, M.J.Arvai, A.S.Yates, J.R.Tainer, J.A.Getzoff, E.D.

(2010) J.Biol.Chem. 285: 31581-31589

  • DOI: 10.1074/jbc.M109.072496

  • PubMed Abstract: 
  • Inducible nitric-oxide synthase (iNOS) produces biologically stressful levels of nitric oxide (NO) as a potent mediator of cellular cytotoxicity or signaling. Yet, how this nitrosative stress affects iNOS function in vivo is poorly understood. Here w ...

    Inducible nitric-oxide synthase (iNOS) produces biologically stressful levels of nitric oxide (NO) as a potent mediator of cellular cytotoxicity or signaling. Yet, how this nitrosative stress affects iNOS function in vivo is poorly understood. Here we define two specific non-heme iNOS nitrosation sites discovered by combining UV-visible spectroscopy, chemiluminescence, mass spectrometry, and x-ray crystallography. We detected auto-S-nitrosylation during enzymatic turnover by using chemiluminescence. Selective S-nitrosylation of the ZnS(4) site, which bridges the dimer interface, promoted a dimer-destabilizing order-to-disorder transition. The nitrosated iNOS crystal structure revealed an unexpected N-NO modification on the pterin cofactor. Furthermore, the structurally defined N-NO moiety is solvent-exposed and available to transfer NO to a partner. We investigated glutathione (GSH) as a potential transnitrosation partner because the intracellular GSH concentration is high and NOS can form S-nitrosoglutathione. Our computational results predicted a GSH binding site adjacent to the N-NO-pterin. Moreover, we detected GSH binding to iNOS with saturation transfer difference NMR spectroscopy. Collectively, these observations resolve previous paradoxes regarding this uncommon pterin cofactor in NOS and suggest means for regulating iNOS activity via N-NO-pterin and S-NO-Cys modifications. The iNOS self-nitrosation characterized here appears appropriate to help control NO production in response to cellular conditions.


    Organizational Affiliation

    Department of Molecular Biology, The Skaggs Institute for Chemical Biology, La Jolla, California 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Nitric oxide synthase, inducible
A, B
433Mus musculusMutation(s): 0 
Gene Names: Nos2 (Inosl)
EC: 1.14.13.39
Find proteins for P29477 (Mus musculus)
Go to UniProtKB:  P29477
Small Molecules
Ligands 8 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
AT2
Query on AT2

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A, B
ETHYL 4-[(4-METHYLPYRIDIN-2-YL)AMINO]PIPERIDINE-1-CARBOXYLATE
C14 H21 N3 O2
LNRMJBWADUSJTA-UHFFFAOYSA-N
 Ligand Interaction
GOL
Query on GOL

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A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

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A, B
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
HEM
Query on HEM

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A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
H4B
Query on H4B

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A, B
5,6,7,8-TETRAHYDROBIOPTERIN
C9 H15 N5 O3
FNKQXYHWGSIFBK-RPDRRWSUSA-N
 Ligand Interaction
NO
Query on NO

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A, B
NITRIC OXIDE
Nitrogen monoxide
N O
ODUCDPQEXGNKDN-UHFFFAOYAM
 Ligand Interaction
BOG
Query on BOG

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B
B-OCTYLGLUCOSIDE
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
AT2IC50: 350 nM (85) BINDINGDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.204 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 214.114α = 90.00
b = 214.114β = 90.00
c = 116.542γ = 120.00
Software Package:
Software NamePurpose
HKL-2000data scaling
DENZOdata reduction
XFITdata reduction
CNSrefinement
ADSCdata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-07-21
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance