Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase

Georges Chreifi, Huiying Li, Craig McInnes, Colin Gibson, Colin Suckling, Thomas L Poulos

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The nitric oxide synthase (NOS) dimer is stabilized by a Zn2+ ion coordinated to four symmetry-related Cys residues exactly along the dimer 2-fold axis. Each of the two essential tetrahydrobiopterin (H4B) molecules in the dimer interacts directly with the heme, and each H4B molecule is ∼15 Å from the Zn2+. We have determined the crystal structures of the bovine endothelial NOS dimer oxygenase domain bound to three different pterin analogues, which reveal an intimate structural communication between the H4B and Zn2+ sites. The binding of one of these compounds, 6-acetyl-2-amino-7,7-dimethyl-7,8-dihydro-4(3H)-pteridinone (1), to the pterin site and Zn2+ binding are mutually exclusive. Compound 1both directly and indirectly disrupts hydrogen bonding between key residues in the Zn2+ binding motif, resulting in destabilization of the dimer and a complete disruption of the Zn2+ site. Addition of excess Zn2+ stabilizes the Zn2+ site at the expense of weakened binding of 1. The unique structural features of 1 that disrupt the dimer interface are extra methyl groups that extend into the dimer interface and force a slight opening of the dimer, thus resulting in disruption of the Zn2+ site. These results illustrate a very delicate balance of forces and structure at the dimer interface that must be maintained to properly form the Zn2+, pterin, and substrate binding sites.
LanguageEnglish
JournalBiochemistry
Early online date12 May 2014
DOIs
Publication statusPublished - 2014

Fingerprint

Pterins
Nitric Oxide Synthase
Dimers
Zinc
Binding Sites
Communication
Pteridines
Oxygenases
Nitric Oxide Synthase Type III
Hydrogen Bonding
Heme
Ions
sapropterin
Molecules
Hydrogen bonds
Crystal structure

Keywords

  • crystal structures
  • nitric oxide synthase (NOS)
  • tetrahydrobiopterin binding sites
  • H4B

Cite this

Chreifi, Georges ; Li, Huiying ; McInnes, Craig ; Gibson, Colin ; Suckling, Colin ; Poulos, Thomas L. / Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase. In: Biochemistry. 2014.
@article{0aeb7384677949db8f66a6cc1c789cb4,
title = "Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase",
abstract = "The nitric oxide synthase (NOS) dimer is stabilized by a Zn2+ ion coordinated to four symmetry-related Cys residues exactly along the dimer 2-fold axis. Each of the two essential tetrahydrobiopterin (H4B) molecules in the dimer interacts directly with the heme, and each H4B molecule is ∼15 {\AA} from the Zn2+. We have determined the crystal structures of the bovine endothelial NOS dimer oxygenase domain bound to three different pterin analogues, which reveal an intimate structural communication between the H4B and Zn2+ sites. The binding of one of these compounds, 6-acetyl-2-amino-7,7-dimethyl-7,8-dihydro-4(3H)-pteridinone (1), to the pterin site and Zn2+ binding are mutually exclusive. Compound 1both directly and indirectly disrupts hydrogen bonding between key residues in the Zn2+ binding motif, resulting in destabilization of the dimer and a complete disruption of the Zn2+ site. Addition of excess Zn2+ stabilizes the Zn2+ site at the expense of weakened binding of 1. The unique structural features of 1 that disrupt the dimer interface are extra methyl groups that extend into the dimer interface and force a slight opening of the dimer, thus resulting in disruption of the Zn2+ site. These results illustrate a very delicate balance of forces and structure at the dimer interface that must be maintained to properly form the Zn2+, pterin, and substrate binding sites.",
keywords = "crystal structures, nitric oxide synthase (NOS) , tetrahydrobiopterin binding sites , H4B",
author = "Georges Chreifi and Huiying Li and Craig McInnes and Colin Gibson and Colin Suckling and Poulos, {Thomas L}",
note = "Date of Acceptance:12/05/2014 This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Biochemistry, copyright {\circledC} American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/bi5003986.",
year = "2014",
doi = "10.1021/bi5003986",
language = "English",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",

}

Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase. / Chreifi, Georges; Li, Huiying; McInnes, Craig; Gibson, Colin; Suckling, Colin; Poulos, Thomas L.

In: Biochemistry, 2014.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase

AU - Chreifi, Georges

AU - Li, Huiying

AU - McInnes, Craig

AU - Gibson, Colin

AU - Suckling, Colin

AU - Poulos, Thomas L

N1 - Date of Acceptance:12/05/2014 This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Biochemistry, copyright © American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/bi5003986.

PY - 2014

Y1 - 2014

N2 - The nitric oxide synthase (NOS) dimer is stabilized by a Zn2+ ion coordinated to four symmetry-related Cys residues exactly along the dimer 2-fold axis. Each of the two essential tetrahydrobiopterin (H4B) molecules in the dimer interacts directly with the heme, and each H4B molecule is ∼15 Å from the Zn2+. We have determined the crystal structures of the bovine endothelial NOS dimer oxygenase domain bound to three different pterin analogues, which reveal an intimate structural communication between the H4B and Zn2+ sites. The binding of one of these compounds, 6-acetyl-2-amino-7,7-dimethyl-7,8-dihydro-4(3H)-pteridinone (1), to the pterin site and Zn2+ binding are mutually exclusive. Compound 1both directly and indirectly disrupts hydrogen bonding between key residues in the Zn2+ binding motif, resulting in destabilization of the dimer and a complete disruption of the Zn2+ site. Addition of excess Zn2+ stabilizes the Zn2+ site at the expense of weakened binding of 1. The unique structural features of 1 that disrupt the dimer interface are extra methyl groups that extend into the dimer interface and force a slight opening of the dimer, thus resulting in disruption of the Zn2+ site. These results illustrate a very delicate balance of forces and structure at the dimer interface that must be maintained to properly form the Zn2+, pterin, and substrate binding sites.

AB - The nitric oxide synthase (NOS) dimer is stabilized by a Zn2+ ion coordinated to four symmetry-related Cys residues exactly along the dimer 2-fold axis. Each of the two essential tetrahydrobiopterin (H4B) molecules in the dimer interacts directly with the heme, and each H4B molecule is ∼15 Å from the Zn2+. We have determined the crystal structures of the bovine endothelial NOS dimer oxygenase domain bound to three different pterin analogues, which reveal an intimate structural communication between the H4B and Zn2+ sites. The binding of one of these compounds, 6-acetyl-2-amino-7,7-dimethyl-7,8-dihydro-4(3H)-pteridinone (1), to the pterin site and Zn2+ binding are mutually exclusive. Compound 1both directly and indirectly disrupts hydrogen bonding between key residues in the Zn2+ binding motif, resulting in destabilization of the dimer and a complete disruption of the Zn2+ site. Addition of excess Zn2+ stabilizes the Zn2+ site at the expense of weakened binding of 1. The unique structural features of 1 that disrupt the dimer interface are extra methyl groups that extend into the dimer interface and force a slight opening of the dimer, thus resulting in disruption of the Zn2+ site. These results illustrate a very delicate balance of forces and structure at the dimer interface that must be maintained to properly form the Zn2+, pterin, and substrate binding sites.

KW - crystal structures

KW - nitric oxide synthase (NOS)

KW - tetrahydrobiopterin binding sites

KW - H4B

UR - http://pubs.acs.org/loi/bichaw

U2 - 10.1021/bi5003986

DO - 10.1021/bi5003986

M3 - Article

JO - Biochemistry

T2 - Biochemistry

JF - Biochemistry

SN - 0006-2960

ER -