Crystal Structure of Nitric Oxide Synthase Bound to Nitro Indazole Reveals a Novel Inactivation Mechanism

Raman, C.S.; Li, Huiying; Martásek, Pavel; Southan, Garry J.; Masters, B.S.S.; Poulos, T.L.

doi:10.1021/bi010957u

Cited by 79 publications

(75 citation statements)

References 52 publications

(80 reference statements)

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“…The similar binding geometries of L-Arg and NOHA (37,38), as well as crystallographic structural analyses of NOS in the presence of hydroxyguanidines (77,78), led us to exclude that differences in the positioning of the guanidinium moiety or significant steric effects could account for a Fe-CO frequency shift of up to 30 cm Ϫ1 (41). The RR spectra of Fe III and Fe II -CO iNOSoxy complexes presented here did not show any significant differences in the frequencies of core-size sensitive porphyrin modes, suggesting very similar heme conformations and heme-protein interactions for the series of bound L-Arg analogues.…”

Section: Various Causes For the Changes In Fementioning

confidence: 65%

Role of Arginine Guanidinium Moiety in Nitric-oxide Synthase Mechanism of Oxygen Activation

Giroud

Moreau

Mattioli

et al. 2010

Journal of Biological Chemistry

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Section: Various Causes For the Changes In Fementioning

confidence: 65%

Role of Arginine Guanidinium Moiety in Nitric-oxide Synthase Mechanism of Oxygen Activation

Giroud

Moreau

Mattioli

et al. 2010

Journal of Biological Chemistry

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“…This charge may interact with the partial negative charge of the oxygen ligand and freeze an eventual ferrous dioxygen-ferric superoxide equilibrium in the ferric superoxide state. This hypothesis is supported by the 2-4 nm smaller blue shift of heme-oxy II spectra in the presence of NHA with respect to those in the presence of L-Arg, which has a more pronounced positive charge (39).…”

Section: Mechanism Of Formation and Possible Physiologicalmentioning

confidence: 88%

“…In contrast, in the presence of pterin alone, the ferrous oxygen state of heme-oxy I may be favored. Changes in the position of the propionate accompanied by elimination of BH4 binding have been reported for the complex of eNOS oxy with 3-bromo-7-nitroindazole (39).…”

Section: Mechanism Of Formation and Possible Physiologicalmentioning

confidence: 94%

“…Crystallographic studies have repeatedly demonstrated that BH4 has no major effects on the structure of NOS in general or on the active site structure in particular, despite its close proximity (39,40). Perhaps the clue to understanding the effects of pterin on the nature of the oxyferrous complex may be found in its interaction with one of the propionates of the heme, which it shares with bound substrate (39,41,42). Conceivably, a shift in the position of this propionate in the presence of pterin and/or substrate may decrease the polarity in the vicinity of the heme-bound ligand.…”

Section: Mechanism Of Formation and Possible Physiologicalmentioning

confidence: 99%

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Evidence of Two Distinct Oxygen Complexes of Reduced Endothelial Nitric Oxide Synthase

Marchal

Gorren

Sørlie

et al. 2004

Journal of Biological Chemistry

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Oxygen binding to the oxygenase domain of reduced endothelial nitric oxide synthase (eNOS) results in two distinct species differing in their Soret and visible absorbance maxima and in their capacity to exchange oxygen by CO. At 7°C, heme-oxy I (with maxima at 420 and 560 nm) is formed very rapidly (k on Ϸ 2.5⅐10 6 M ؊1 ⅐s ؊1 ) in the absence of substrate but in the presence of pterin cofactor. It is capable of exchanging oxygen with CO at ؊30°C. Heme-oxy II is formed more slowly (k on Ϸ 3⅐10 5 M ؊1 ⅐s ؊1 ) in the presence of substrate, regardless of the presence of pterin. It is also formed in the absence of both substrate and pterin. In contrast to heme-oxy I, it cannot exchange oxygen with CO at cryogenic temperature. In the presence of arginine, heme-oxy II is characterized by absorbance maxima near 432, 564, and 597 nm. When arginine is replaced by N-hydroxyarginine, and also in the absence of both substrate and pterin, its absorbance maxima are blue-shifted to 428, 560, and 593 nm. Heme-oxy I seems to resemble the ferrous dioxygen complex observed in many hemoproteins, including cytochrome P450. Heme-oxy II, which is the oxygen complex competent for product formation, appears to represent a distinct conformation in which the electronic configuration is essentially locked in the ferric superoxide complex.Activation of molecular oxygen by nitric oxide synthase precedes NO 1 biosynthesis by a yet incompletely known reaction mechanism. A study of the steps following oxygen binding and NO formation is important since NO is a mediator of a wide range of physiological and pathophysiological processes in humans and other mammals (1-6). The formation of NO is catalyzed by nitric oxide synthases (NOS; EC 1.14.13.39) via a two-step mechanism. The substrate, L-Arg, is first converted to N G -hydroxy-L-Arg (NHA) at the heme active site. In the second step, NHA is further oxidized to NO and citrulline (3). In both steps, oxygen binding occurs after a one-electron reduction of the ferric heme. Prior to product formation, an electron stemming from tetrahydrobiopterin (BH4) then further reduces the ferrous oxygen complex.Despite much effort, the reaction mechanism of these steps is still unclear. Even the spectral properties of the oxyferrous complex are not yet defined; conflicting observations report absorbance maxima differing by up to 15 nm. The origin of these differences is unknown. The strongest differences are those between observations at cryogenic temperatures yielding maxima in the 417-419-nm region (7-9) and observations at higher temperatures by rapid scan techniques yielding considerably red-shifted maxima (430 -432 nm) (10 -14). However, this distinction is not clear-cut; in some cases, low wavelength maxima are also found by rapid scan spectroscopy (11), and high wavelength maxima are also found by low temperature UV-visible spectroscopy (9).To clarify this confusing situation, we reanalyzed the temporal evolution of the spectral changes occurring upon oxygen binding to reduced eNOS oxygenase domain by rapi...

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“…Certain fungal CPOs and bacterial P450s have been genetically engineered for large-scale biotransformations (7)(8)(9)(10). The active sites of these three protein families, known in detail from a number of x-ray crystal structures (4,(11)(12)(13), are remarkably similar. All three have an iron-protoporphyrin IX center coordinated to a cysteine thiolate.…”

Section: Oxygen Activation By Heme Proteinsmentioning

confidence: 99%

The bioinorganic chemistry of iron in oxygenases and supramolecular assemblies

Groves

2003

Proc. Natl. Acad. Sci. U.S.A.

305

174

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The bioinorganic chemistry of iron is central to life processes. Organisms must recruit iron from their environment, control iron storage and trafficking within cells, assemble the complex, iron-containing redox cofactors of metalloproteins, and manage a myriad of biochemical transformations by those enzymes. The coordination chemistry and the variable oxidation states of iron provide the essential mechanistic machinery of this metabolism. Our current understanding of several aspects of the chemistry of iron in biology are discussed with an emphasis on the oxygen activation and transfer reactions mediated by heme and nonheme iron proteins and the interactions of amphiphilic iron siderophores with lipid membranes.

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Crystal Structure of Nitric Oxide Synthase Bound to Nitro Indazole Reveals a Novel Inactivation Mechanism

Cited by 79 publications

References 52 publications

Role of Arginine Guanidinium Moiety in Nitric-oxide Synthase Mechanism of Oxygen Activation

Role of Arginine Guanidinium Moiety in Nitric-oxide Synthase Mechanism of Oxygen Activation

Evidence of Two Distinct Oxygen Complexes of Reduced Endothelial Nitric Oxide Synthase

The bioinorganic chemistry of iron in oxygenases and supramolecular assemblies

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