1ED6

BOVINE ENDOTHELIAL NITRIC OXIDE SYNTHASE HEME DOMAIN COMPLEXED WITH L-NIO (H4B FREE)

• PDB DOI: https://doi.org/10.2210/pdb1ED6/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Bos taurus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2000-01-26 Released: 2001-01-31 
• Deposition Author(s): Raman, C.S., Li, H., Martasek, P., Southan, G.J., Masters, B.S.S., Poulos, T.L.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.05 Å
• R-Value Free: 0.275 
• R-Value Work: 0.241 
• R-Value Observed: 0.241 

Literature

Crystallographic studies on endothelial nitric oxide synthase complexed with nitric oxide and mechanism-based inhibitors.

Li, H., Raman, C.S., Martasek, P., Masters, B.S., Poulos, T.L.

(2001) Biochemistry 40: 5399-5406

• PubMed: 11331003 
• DOI: https://doi.org/10.1021/bi002658v
• Primary Citation of Related Structures:  
  1ED6, 1FOI, 1FOL, 1FOO, 1FOP


• PubMed Abstract: 
  

  The crystal structure of the endothelial nitric oxide synthase (NOS) heme domain complexed with NO reveals close hydrogen bonding interactions between NO and the terminal guanidino nitrogen of the substrate, L-arginine. Dioxygen is expected to bind in a similar mode which will facilitate proton abstraction from L-Arg to dioxygen, a required step for O-O bond cleavage. Structures of mechanism-based NOS inhibitors, N(5)-(1-iminoethyl)-L-ornithine and N-(3-(aminomethyl)benzyl)acetamidine, provide clues on how this class of compounds operate as suicide substrate inhibitors leading to heme oxidation.

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Organizational Affiliation: 

Departments of Molecular Biology & Biochemistry and Physiology & Biophysics and Program in Macromolecular Structure, University of California, Irvine 92697-3900, USA.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 101.64 kDa 
• Atom Count: 7,105 
• Modelled Residue Count: 830 
• Deposited Residue Count: 888 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
NITRIC OXIDE SYNTHASE	A, B	444	Bos taurus	Mutation(s): 0  EC: 1.14.13.39
UniProt
Find proteins for P29473 (Bos taurus) Explore P29473  Go to UniProtKB:  P29473

Small Molecules

Ligands 6 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
HEM	E [auth A], J [auth B]	PROTOPORPHYRIN IX CONTAINING FE C34 H32 Fe N4 O4 KABFMIBPWCXCRK-RGGAHWMASA-L
ILO	F [auth A], K [auth B]	N5-IMINOETHYL-L-ORNITHINE C7 H15 N3 O2 UYZFAUAYFLEHRC-LURJTMIESA-N
CAD	G [auth A], L [auth B]	CACODYLIC ACID C2 H7 As O2 OGGXGZAMXPVRFZ-UHFFFAOYSA-N
GOL	H [auth A], M [auth B]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
ZN	D [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
ACT	C [auth A], I [auth B]	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.05 Å
• R-Value Free: 0.275 
• R-Value Work: 0.241 
• R-Value Observed: 0.241 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 59.12	α = 90
b = 106.16	β = 90
c = 156.7	γ = 90

Software Package:

Software Name	Purpose
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2001-01-31 
Deposition Author(s): Raman, C.S., Li, H., Martasek, P., Southan, G.J., Masters, B.S.S., Poulos, T.L.

Revision History  

• Version 1.0: 2001-01-31
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Non-polymer description, Version format compliance
• Version 1.3: 2024-02-07
  Changes: Data collection, Database references, Derived calculations