Endogenous nitric oxide regulates the recovery of the radiation-resistant bacterium
            <i>Deinococcus radiodurans</i>
            from exposure to UV light

Patel, Bhumit A.; Moreau, Magali; Widom, Joanne; Chen, Huan; Li, Yin; Hua, Yuejin; Crane, Brian R.

doi:10.1073/pnas.0907262106

Cited by 63 publications

(70 citation statements)

References 51 publications

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“…As a result, several hypotheses about NOS biological activity are still competing. Among them, bacterial NOSs could intervene in the survival and virulence of some pathogenic bacteria [236,240,241], in their recovery after oxidative damages [242], in detoxification processes [243] or in the biosynthesis of toxins [226,235,[244][245][246]. In this puzzling picture, the elucidation of the molecular mechanism might provide a new reading frame for the catalytic functionning and the biological activity of these numerous NOSlike proteins.…”

Section: Discussionmentioning

confidence: 98%

The molecular mechanism of mammalian NO-synthases: A story of electrons and protons

Santolini

2011

Journal of Inorganic Biochemistry

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Section: Discussionmentioning

confidence: 98%

The molecular mechanism of mammalian NO-synthases: A story of electrons and protons

Santolini

2011

Journal of Inorganic Biochemistry

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“…Following different hypotheses, Nudler and colleagues (22)(23)(24) proposed that bacNOSs could intervene in a series of functions related to host-pathogen interaction such as protection against oxidative stress (22), pathogen survival and virulence (23), or defense against antibiotics (24). Recently, Crane suggested that D. radiodurans NOS could intervene in the recovery processes of bacteria subject to a UV stress (25). Because NO production is primarily used by the host as a bactericidal weapon, we feel that NO is not the most appropriate molecule to elicit a concerted response against the host immune system.…”

mentioning

confidence: 99%

The Proximal Hydrogen Bond Network Modulates Bacillus subtilis Nitric-oxide Synthase Electronic and Structural Properties

Brunel

Wilson

Henry

et al. 2011

Journal of Biological Chemistry

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Bacterial nitric-oxide synthase (NOS)-like proteins are believed to be genuine NOSs. As for cytochromes P450 (CYPs), NOS-proximal ligand is a thiolate that exerts a push effect crucial for the process of dioxygen activation. Unlike CYPs, this catalytic electron donation seems controlled by a hydrogen bond (H-bond) interaction between the thiolate ligand and a vicinal tryptophan. Variations of the strength of this H-bond could provide a direct way to tune the stability along with the electronic and structural properties of NOS. We generated five different mutations of bsNOS Trp 66 , which can modulate this proximal H-bond. We investigated the effects of these mutations on different NOS complexes (Fe III , Fe II CO, and Fe II NO), using a combination of UV-visible absorption, EPR, FTIR, and resonance Raman spectroscopies. Our results indicate that (i) the proximal H-bond modulation can selectively decrease or increase the electron donating properties of the proximal thiolate, (ii) this modulation controls the -competition between distal and proximal ligands, (iii) this H-bond controls the stability of various NOS intermediates, and (iv) a fine tuning of the electron donation by the proximal ligand is required to allow at the same time oxygen activation and to prevent uncoupling reactions.

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“…1). CuFL1 has been used to monitor NO production in bacterial cell cultures with great success (14,15), but to improve its applicability a cell-trappable version of the ligand is required. Cell-trappability is a key feature for biological experiments in intact tissues for which continual perfusion of tissue slices with artificial physiological saline solution is required.…”

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confidence: 99%

Visualization of nitric oxide production in the mouse main olfactory bulb by a cell-trappable copper(II) fluorescent probe

McQuade

Lowe

et al. 2010

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

116

102

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We report the visualization of NO production using fluorescence in tissue slices of the mouse main olfactory bulb. This discovery was possible through the use of a novel, cell-trappable probe for intracellular nitric oxide detection based on a symmetric scaffold with two NO-reactive sites. Ester moieties installed onto the fluorescent probe are cleaved by intracellular esterases to yield the corresponding negatively charged, cell-impermeable acids. The trappable probe Cu 2 ðFL2EÞ and the membrane-impermeable acid derivative Cu 2 ðFL2AÞ respond rapidly and selectively to NO in buffers that simulate biological conditions, and application of Cu 2 ðFL2EÞ leads to detection of endogenously produced NO in cell cultures and olfactory bulb brain slices.fluorescent sensing | NO | olfaction | trappable probe | fluorescence microscopy N itric oxide (NO) is important for biological signaling. It activates soluble guanylyl cyclase, initiating a signaling cascade that promotes vascular smooth muscle dilation (1-3). Nitric oxide produced in the nervous system has been implicated in neurotransmission (4), and the immune system generates NO as a defense against pathogens (5). Unregulated nitric oxide production has been associated with pathological conditions such as cancer, ischemia, septic shock, inflammation, and neurodegeneration (6).Because of its various biological consequences, investigating the generation, translocation, and utilization of NO continues to be an active area of research. A major limitation to advances in the field, however, has been the dearth of selective tools for visualization of biological NO, for example by fluorescence microscopy. Detection of nitric oxide offers many challenges. NO reacts rapidly in vivo with dioxygen, oxygen-generated radicals such as superoxide, amines, thiols, and metal centers (7,8). It also diffuses readily from its point of origin (9), making rapid detection desirable for uncovering both its production site and function. Moreover, NO is produced at concentrations as low as ∼100 picomolar, so it is essential to have an NO probe with a low detection limit (10). Fluorescent sensors can be designed to accommodate the properties of NO under physiological conditions, making this technique particularly valuable for in vivo nitric oxide imaging.Transition metal complexes have been investigated as platforms for NO detection (11). The strategy is to incorporate a fluorophore into a ligand that is quenched either by intracellular photoinduced electron transfer and/or by coordination to a paramagnetic or heavy metal ion. Fluorescence is restored by reduction of the metal and/or displacement of the ligand upon reaction of the probe with NO. CuFL1 (Fig. 1) is an excellent example of such a metal-based cellular NO imaging agent (12, 13). CuFL1 satisfies many of the requirements of a good sensor. It is nontoxic, cell membrane permeable, has low energy excitation and emission wavelengths, responds directly and selectively to NO, and exhibits dramatic fluorescence enhancement upon reaction with...

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Endogenous nitric oxide regulates the recovery of the radiation-resistant bacterium Deinococcus radiodurans from exposure to UV light

Cited by 63 publications

References 51 publications

The molecular mechanism of mammalian NO-synthases: A story of electrons and protons

The molecular mechanism of mammalian NO-synthases: A story of electrons and protons

The Proximal Hydrogen Bond Network Modulates Bacillus subtilis Nitric-oxide Synthase Electronic and Structural Properties

Visualization of nitric oxide production in the mouse main olfactory bulb by a cell-trappable copper(II) fluorescent probe

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