A dinuclear nickel complex modeling of the Nid(ii)-Nip(i) state of the active site of acetyl CoA synthase

Matsumoto, Tsuyoshi; Ito, Misako; Kotera, Mai; Tatsumi, Kazuyuki

doi:10.1039/b924915j

Cited by 29 publications

(37 citation statements)

References 36 publications

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“…7a,b,d,e Complex 1 reproduces closely structural parameters of the oxidized form of the A-cluster (A ox ), the dinuclear (Ni 2+ Ni 2+ ) portion of acetyl-CoA-synthase/CO-dehydrogenase. 2,12 Despite the fact that 1 is a homodimeric complex, the Ni−Ni distance of 2.7016 Å may additionally be relevant from a functional perspective for a potential hydrogenase activity (see As we expected, the coordination geometry is quite different around the Zn 2+ ions in 2 (Table 1). Each crystallographically independent Zn center is in a distorted tetrahedral environment, and as in the case of 1, each Zn 2+ ion reaches a coordination number of four with a sulfur atom bridging two metal centers of the dimeric structure observed ( Figure 2).…”

Section: ■ Results and Discussionmentioning

confidence: 89%

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand

Mondragón

Flores-Álamo²,

Martínez‐Alanis³

et al. 2014

Inorg. Chem.

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Basic methanolysis of a sterically hindered aminobis(S-arylthiocarbamate) affords a novel aminobis(thiophenolate) pincer-type ligand NS22–; the in situ generated dianion reacts cleanly with Ni2+ and Zn2+ resulting in dimeric complexes with bridging thiophenolate ligands, as determined spectroscopically and by X-ray crystallography. The C2-symmetric [Ni(NS2)]2 dimer (1) has a square planar coordination geometry around the Ni2+ ions, while the [Zn(NS2)]2 analogue (2) is characterized by a distorted tetrahedral geometry around each independent Zn2+ ion. Addition of the neutral monodentate donor L = 2,6-xylylisocyanide to [Ni(NS2)]2 affords the monomeric complex [LNi(NS2)] (3), which is characterized in the solid state by a square planar geometry with the isocyanide donor trans to the tertiary amine of NS2. The pincer NS2 ligand provides redox plasticity to 1, manifested in the accessibility of the putative Ni+Ni+ and Ni3+Ni3+ dimeric complexes, based on comparative cyclic voltammetry studies with 2 and 3. The redox properties of 1 endow it with hydrogenase-type activity, as evidenced in the electrocatalytic reduction of protons in a mixed aqueous/organic phase, as well as the oxidation of hydrides from NaBH(OAc)3. Both 1 and 3 are resilient under protic and oxidative conditions, as evidenced in reactivity tests monitored by UV–vis spectroscopy.

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Section: ■ Results and Discussionmentioning

confidence: 89%

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand

Mondragón

Flores-Álamo²,

Martínez‐Alanis³

et al. 2014

Inorg. Chem.

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“…2.65 Å, enticingly close to bonding distance. A possible dependence on oxidation state was noted, with [Ni II Ni II ] complexes possessing longer Ni-Ni bond distances than the corresponding [Ni I Ni II ] complexes [65]. For the two ACS structures that have been published [11,14], the average Ni p -Ni d distance and hinge angle are ca .…”

Section: 4 Evidence For M-m Bonds In Metalloenzymesmentioning

confidence: 99%

Metal–metal bonds in biology

Lindahl

2012

Journal of Inorganic Biochemistry

102

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Nickel-containing carbon monoxide dehydrogenases, acetyl-CoA synthases, nickel-iron hydrogenases, and diron hydrogenases are distinct metalloenzymes yet they share a number of important characteristics. All are O2-sensitive, with active-sites composed of iron and/or nickel ions coordinated primarily by sulfur ligands. In each case, two metals are juxtaposed at the “heart” of the active site, within range of forming metal-metal bonds. These active-site clusters exhibit multielectron redox abilities and must be reductively activated for catalysis. Reduction potentials are milder than expected based on formal oxidation state changes. When reductively activated, each cluster attacks an electrophilic substrate via an oxidative addition reaction. This affords a two-electron-reduced substrate bound to one or both metals of an oxidized cluster. M-M bonds have been established in hydrogenases where they serve to initiate the oxidative addition of protons and perhaps stabilize active sites in multiple redox states. The same may be true of the CODH and ACS active sites – Ni-Fe and Ni-Ni bonds in these sites may play critical roles in catalysis, stabilizing low-valence states and initiating oxidative addition of CO2 and methyl group cations, respectively. In this article, the structural and functional commonalities of these metalloenzyme active sites are described, and the case is made for the formation and use of metal-metal bonds in each enzyme mentioned. As a post-script, the importance of Fe-Fe bonds in the nitrogenase FeMoco active site is discussed.

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“…5e, that can be methylated by methyl-cobaloxime, and that can further react with CO to form an acetylthioester compound similar to acetyl-CoA. 51,52 In these studies, the compound Ni(dadt Et )Ni(Me)(SDmp), where dadt Et stands for N , N ′-diethyl-3,7-diazanonane-1,9-dithiolate and Dmp for 2,6-dimesitylphenyl, was synthesized as a Ni II –Ni I complex. It had a S = 1/2 EPR signal ( g x , y , z = 2.62, 2.12, 2.00), could be methylated and then react with CO.…”

Section: (Iv) Non-enzymatic Inorganic Compounds That Catalyze Reactimentioning

confidence: 99%

“…a: [(CysGlyCys)Ni]Ni(dppe), 47 b: [Ni II (dppe)Ni II (PhPepS)], 48 c: Methyl-Ni complex, 49 d: [PPN][Ni III (R)-(P(C 6 H 3 -3-SiMe 3 -2-S) 3 )] − , 50 e: Ni II (dadt Et )Ni I (SDmp)-(PPh 3 ). 51 …”

Section: Figmentioning

confidence: 99%

Metal centers in the anaerobic microbial metabolism of CO and CO2

et al. 2011

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Carbon dioxide and carbon monoxide are important components of the carbon cycle. Major research efforts are underway to develop better technologies to utilize the abundant greenhouse gas, CO2, for harnessing ‘green’ energy and producing biofuels. One strategy is to convert CO2 into CO, which has been valued for many years as a synthetic feedstock for major industrial processes. Living organisms are masters of CO2 and CO chemistry and, here, we review the elegant ways that metalloenzymes catalyze reactions involving these simple compounds. After describing the chemical and physical properties of CO and CO2, we shift focus to the enzymes and the metal clusters in their active sites that catalyze transformations of these two molecules. We cover how the metal centers on CO dehydrogenase catalyze the interconversion of CO and CO2 and how pyruvate oxidoreductase, which contains thiamin pyrophosphate and multiple Fe4S4 clusters, catalyzes the addition and elimination of CO2 during intermediary metabolism. We also describe how the nickel center at the active site of acetyl-CoA synthase utilizes CO to generate the central metabolite, acetyl-CoA, as part of the Wood-Ljungdahl pathway, and how CO is channelled from the CO dehydrogenase to the acetyl-CoA synthase active site. We cover how the corrinoid iron–sulfur protein interacts with acetyl-CoA synthase. This protein uses vitamin B12 and a Fe4S4 cluster to catalyze a key methyltransferase reaction involving an organometallic methyl-Co3+ intermediate. Studies of CO and CO2 enzymology are of practical significance, and offer fundamental insights into important biochemical reactions involving metallocenters that act as nucleophiles to form organometallic intermediates and catalyze C–C and C–S bond formations.

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A dinuclear nickel complex modeling of the Nid(ii)-Nip(i) state of the active site of acetyl CoA synthase

Cited by 29 publications

References 36 publications

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand

Metal–metal bonds in biology

Metal centers in the anaerobic microbial metabolism of CO and CO2

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A dinuclear nickel complex modeling of the Nid(ii)-Nip(i) state of the active site of acetyl CoA synthase

Cited by 29 publications

References 36 publications

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS2 Aminobis(thiophenolate) Ligand

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS2 Aminobis(thiophenolate) Ligand

Metal–metal bonds in biology

Metal centers in the anaerobic microbial metabolism of CO and CO2

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Product

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Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand

Electrocatalytic Proton Reduction by Dimeric Nickel Complex of a Sterically Demanding Pincer-type NS₂ Aminobis(thiophenolate) Ligand