Simultaneous nitrosylation and N-nitrosation of a Ni-thiolate model complex of Ni-containing SOD

Truong, Phan T.; Broering, Ellen P.; Dzul, Stephen P.; Chakraborty, Indranil; Stemmler, Timothy L.; Harrop, Todd C.

doi:10.1039/c8sc03321h

Cited by 4 publications

(1 citation statement)

References 84 publications

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“…Their lack of reactivity has often been rationalized either by their sensitivity to the superoxide or derivatives, or by the irreversibility of the Ni III /Ni II redox process . Finally, these two bioinspired strategies have led to the proposal of different mechanisms for the NiSOD reactivity, with the disproportionation of the superoxide occurring through either inner- , or outer-sphere , pathways.…”

Section: Introductionmentioning

confidence: 99%

Mononuclear Ni(II) Complexes with a S3O Coordination Sphere Based on a Tripodal Cysteine-Rich Ligand: pH Tuning of the Superoxide Dismutase Activity

et al. 2019

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The superoxyde dismutase (SOD) activity of mononuclear Ni II complexes, whose structures are inspired by the NiSOD, has been investigated. They have been designed with a sulfur-rich pseudo-peptide ligand, derived from nitrilotriacetic acid (NTA), where the three acid functions are grafted with cysteines (L 3S). Two mononuclear complexes, which exist in pH-dependent proportions, have been fully characterized by a combination of spectroscopic techniques including 1 H NMR, UV-vis, CD, and XAS, together with theoretical calculations. They display similar square-planar S3O coordination, with the three thiolates of the three cysteine moieties from L 3S coordinated to the Ni II ion, together with either a water molecule at physiological pH, as [NiL 3S (OH2)]-, or a hydroxo ion in more basic conditions, as [NiL 3S (OH)] 2-. The 1 H NMR study has revealed that contrary to the hydroxo ligand, the bound water molecule is labile. The CV of both complexes displays an irreversible one-electron oxidation process assigned to the Ni II /Ni III redox system with Epa = 0.48 and 0.31 V vs SCE for NiL 3S (OH2) and NiL 3S (OH), respectively. The SOD activity of both complexes has been tested. Based on the xanthine oxidase assay, an IC50 of about 1 µM has been measured at pH 7.4, where NiL 3S (OH2) is mainly present (93% of the Ni II species), while the IC50 is larger than 100 µM at pH 9.6, where NiL 3S (OH) is the major species (92% of the Ni II species). Interestingly, only NiL 3S (OH2) displays SOD activity, suggesting that the presence of a labile ligand is required. The SOD activity has been also evaluated under catalytic conditions at pH 7.75, where the ratio between NiL 3S (OH2) / NiL 3S (OH) is about (86:14), and a rate constant, kcat = 1.8 10 5 M-1 s-1 has been measured. NiL 3S (OH2) is thus the first low-molecular weight, synthetic, bio-inspired Ni complex that displays catalytic SOD activity in water at physiological pH, although it does not contain any N-donor ligand in its first coordination sphere, as in the NiSOD. Overall, the data evidences that a key structural feature is the presence of a labile ligand in the coordination sphere of the Ni II ion, consistent with an inner sphere mechanism for at least one of the redox reactions.

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Section: Introductionmentioning

confidence: 99%

Mononuclear Ni(II) Complexes with a S3O Coordination Sphere Based on a Tripodal Cysteine-Rich Ligand: pH Tuning of the Superoxide Dismutase Activity

et al. 2019

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Nickel‐Based Metal‐Organic Frameworks Promote Diabetic Wound Healing via Scavenging Reactive Oxygen Species and Enhancing Angiogenesis

Liu,

Chen,

Liu

et al. 2023

Small

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Chronic diabetic wounds remain a worldwide challenge for both the clinic and research. Given the vicious circle of oxidative stress and inflammatory response as well as the impaired angiogenesis of the diabetic wound tissues, the wound healing process is disturbed and poorly responds to the current treatments. In this work, a nickel‐based metal‐organic framework (MOF, Ni‐HHTP) with excellent antioxidant activity and proangiogenic function is developed to accelerate the healing process of chronic diabetic wounds. The Ni‐HHTP can mimic the enzymatic catalytic activities of antioxidant enzymes to eliminate multi‐types of reactive species through electron transfer reactions, which protects cells from oxidative stress‐related damage. Moreover, this Ni‐based MOF can promote cell migration and angiogenesis by activating transforming growth factor‐β1 (TGF‐β1) in vitro and reprogram macrophages to the anti‐inflammatory phenotype. Importantly, Ni‐HHTP effectively promotes the healing process of diabetic wounds by suppressing the inflammatory response and enhancing angiogenesis in vivo. This study reports a versatile and promising MOF‐based nanozyme for diabetic wound healing, which may be extended in combination with other wound dressings to enhance the management of diabetic or non‐healing wounds.

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Reactivity and Structure of Complexes of Small Molecules: Nitric Oxide

Harland

Manickas

Hunt

et al. 2021

Comprehensive Coordination Chemistry III

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Simultaneous nitrosylation and N-nitrosation of a Ni-thiolate model complex of Ni-containing SOD

Abstract: Nitric oxide reacts with a NiSOD model complex to yield a thiolate-ligated/N-nitrosated {NiNO}10 species with unusually labile Ni–NO bonds.

Cited by 4 publications

References 84 publications

Mononuclear Ni(II) Complexes with a S3O Coordination Sphere Based on a Tripodal Cysteine-Rich Ligand: pH Tuning of the Superoxide Dismutase Activity

Mononuclear Ni(II) Complexes with a S3O Coordination Sphere Based on a Tripodal Cysteine-Rich Ligand: pH Tuning of the Superoxide Dismutase Activity

Nickel‐Based Metal‐Organic Frameworks Promote Diabetic Wound Healing via Scavenging Reactive Oxygen Species and Enhancing Angiogenesis

Reactivity and Structure of Complexes of Small Molecules: Nitric Oxide

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