Structural basis for pterin antagonism in nitric-oxide synthase: Development of novel 4-oxo-pteridine antagonists of (6R)-5,6,7,8-tetrahydrobiopterin

Peter Kotsonis, Lothar G. Fröhlich, C. S. Raman, Huiying Li, Michael Berg, Rainer Gerwig, Viola Groehn, Yonghan Kang, Najim Al-Masoudi, Shahriyar Taghavi-Moghadam, Detlev Mohr, Ursula Münch, Joachim Schnabel, Pavel Martásek, Bettie S.S. Masters, Hartmut Strobel, Thomas Poulos, Hans Matter, Wolfgang Pfleiderer, Harald H.H.W. Schmidt

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Pathological nitric oxide (NO) generation in sepsis, inflammation, and stroke may be therapeutically controlled by inhibiting NO synthases (NOS). Here we targeted the (6R)-5,6,7,8-tetrahydro-L-biopterin (H4Bip)-binding site of NOS, which, upon cofactor binding, maximally increases enzyme activity and NO production from substrate L-arginine. The first generation of H 4Bip-based NOS inhibitors employed a 4-amino pharmacophore of H 4Bip analogous to antifolates such as methotrexate. We developed a novel series of 4-oxo-pteridine derivatives that were screened for inhibition against neuronal NOS (NOS-I) and a structure-activity relationship was determined. To understand the structural basis for pterin antagonism, selected derivatives were docked into the NOS pterin binding cavity. Using a reduced 4-oxo-pteridine scaffold, derivatives with certain modifications such as electron-rich aromatic phenyl or benzoyl groups at the 5- and 6-positions, were discovered to markedly inhibit NOS-I, possibly due to hydrophobic and electrostatic interactions with Phe462 and Ser104, respectively, within the pterin binding pocket. One of the most effective 4-oxo compounds and, for comparisons an active 4-amino derivative, were then co-crystallized with the endothelial NOS (NOS-III) oxygenase domain and this structure solved to confirm the hypothetical binding modes. Collectively, these findings suggest (i) that, unlike the antifolate principle, the 4-amino substituent is not essential for developing pterin-based NOS inhibitors and (ii), provide a steric and electrostatic basis for their rational design.

Original languageEnglish (US)
Pages (from-to)49133-49141
Number of pages9
JournalJournal of Biological Chemistry
Volume276
Issue number52
DOIs
StatePublished - Dec 28 2001

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Kotsonis, P., Fröhlich, L. G., Raman, C. S., Li, H., Berg, M., Gerwig, R., Groehn, V., Kang, Y., Al-Masoudi, N., Taghavi-Moghadam, S., Mohr, D., Münch, U., Schnabel, J., Martásek, P., Masters, B. S. S., Strobel, H., Poulos, T., Matter, H., Pfleiderer, W., & Schmidt, H. H. H. W. (2001). Structural basis for pterin antagonism in nitric-oxide synthase: Development of novel 4-oxo-pteridine antagonists of (6R)-5,6,7,8-tetrahydrobiopterin. Journal of Biological Chemistry, 276(52), 49133-49141. https://doi.org/10.1074/jbc.M011469200