Synthesis of a Molecular Mo2Fe6S9 Cluster with the Topology of the PN Cluster of Nitrogenase by Rearrangement of an Edge-Bridged Mo2Fe6S8 Double Cubane

Zhang, Yugen; Holm, R. H.

doi:10.1021/ja0214633

Cited by 107 publications

(182 citation statements)

References 27 publications

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“…Structurally, it represents a high-nuclearity, Fe/ S-only cluster that can be viewed as two [4Fe-4S] subclusters sharing a 6 -sulfide. Such a ''modular'' composition suggests that the P-cluster is formed through the fusion of its substructural units, a reaction mechanism that is well established in synthetic inorganic chemistry (8) and further supported by recent advances toward successful synthesis of P-cluster topologs (9)(10)(11)(12). Biological evidence of such a fusion mechanism came from studies of three FeMoco-deficient forms of A. vinelandii MoFe protein (Fig.…”

mentioning

confidence: 89%

P-cluster maturation on nitrogenase MoFe protein

Fay

Lee

et al. 2007

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

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Biosynthesis of nitrogenase P-cluster has attracted considerable attention because it is biologically important and chemically unprecedented. Previous studies suggest that P-cluster is formed from a precursor consisting of paired [4Fe-4S]-like clusters and that P-cluster is assembled stepwise on MoFe protein, i.e., one cluster is assembled before the other. Here, we specifically tackle the assembly of the second P-cluster by combined biochemical and spectroscopic approaches. By using a P-cluster maturation assay that is based on purified components, we show that the maturation of the second P-cluster requires the concerted action of NifZ, Fe protein, and MgATP and that the action of NifZ is required before that of Fe protein/MgATP, suggesting that NifZ may act as a chaperone that facilitates the subsequent action of Fe protein/ MgATP. Furthermore, we provide spectroscopic evidence that the [4Fe-4S] cluster-like fragments can be converted to P-clusters, thereby firmly establishing the physiological relevance of the previously identified P-cluster precursor. (Fig. 1A) contains two unique clusters per ␣␤-subunit pair: the [8Fe-7S] P-cluster (6), which is located at the ␣␤-subunit interface, and the [Mo-7Fe-9S-X-homocitrate] † iron-molybdenum cofactor (FeMoco) (7), which is positioned within the ␣-subunit. Nitrogenase catalysis involves a series of complex formation and dissociation between the Fe protein and the MoFe protein, during which process the electrons are sequentially transferred from the [4Fe-4S] cluster of the Fe protein, through the P-cluster, to the FeMoco within the MoFe protein, where substrate reduction eventually occurs. The complexity of nitrogenase reaction mechanism is undoubtedly associated with the presence of complex metalloclusters in the enzyme, namely, the P-cluster and FeMoco, the structure and function of which have served as one of the central topics in nitrogenase research for decades.The P-cluster holds a unique place in nitrogenase chemistry. Catalytically, it serves as a ''hub'' that mediates the shuffling of electrons between the metal centers of the Fe protein and the MoFe protein. Structurally, it represents a high-nuclearity, Fe/ S-only cluster that can be viewed as two [4Fe-4S] subclusters sharing a 6 -sulfide. Such a ''modular'' composition suggests that the P-cluster is formed through the fusion of its substructural units, a reaction mechanism that is well established in synthetic inorganic chemistry (8) and further supported by recent advances toward successful synthesis of P-cluster topologs (9-12). Biological evidence of such a fusion mechanism came from studies of three FeMoco-deficient forms of A. vinelandii MoFe protein (Fig. 1B) that allowed analysis of P-cluster species without the interference of FeMoco. One of these MoFe proteins, designated Av1 ⌬nifH (Fig. 1B, I), was obtained by deleting nifH, the gene encoding the subunit of Fe protein (13-16), whereas another of them, designated Av1 ⌬nifB (Fig. 1B, III), was obtained by deleting nifB, the gene specifically invo...

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mentioning

confidence: 89%

P-cluster maturation on nitrogenase MoFe protein

Fay

Lee

et al. 2007

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

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“…Suitable crystals of a solvated form of (Et 4 N) 3 [4] were acquired by ether diffusion into a 50:1 acetonitrile/water (v/ v) solution at room temperature. Crystals of solvated (Et 4 N) 3 [5] were obtained by either diffusion into a 50:1 acetonitrile/methanol (v/v) solution at room tempareature. Crystals of (Et 4 N) 4 [6]·7MeCN were obtained by the cooling of a concentrated acetonitrile solution to 243 K. Crystals of (Et 4 N) 5 [7]·7MeCN were grown by ether diffusion into an acetonitrile solution at room temperature.…”

Section: X-ray Structure Determinationsmentioning

confidence: 99%

“…Crystals of solvated (Et 4 N) 3 [5] were obtained by either diffusion into a 50:1 acetonitrile/methanol (v/v) solution at room tempareature. Crystals of (Et 4 N) 4 [6]·7MeCN were obtained by the cooling of a concentrated acetonitrile solution to 243 K. Crystals of (Et 4 N) 5 [7]·7MeCN were grown by ether diffusion into an acetonitrile solution at room temperature. Crystals were coated with paratone-N oil and mounted on a Bruker APEX CCD-based diffactometer equipped with an Oxford 700 low-temperature apparatus operating at 193 K for compounds (Et 4 N) 3 [5], (Et 4 N) 4 [6], and (Et 4 N) 5 [7] and 173 K for compound (Et 4 N) 3 [4].…”

Section: X-ray Structure Determinationsmentioning

confidence: 99%

“…Crystals were coated with paratone-N oil and mounted on a Bruker APEX CCD-based diffactometer equipped with an Oxford 700 low-temperature apparatus operating at 193 K for compounds (Et 4 N) 3 [5], (Et 4 N) 4 [6], and (Et 4 N) 5 [7] and 173 K for compound (Et 4 N) 3 [4]. Data were collected with scans of 0.3 s/frame for 45 s, so that 1271-1850 frames were collected for a hemisphere of data for (Et 4 N) 3 [5], (Et 4 N) 4 [6], and (Et 4 N) 5 [7]; data for (Et 4 N) 3 [4] were collected with scans of 0.3 s/frame for 45 s. The first 50 frames were recollected at the end of the data collection to monitor for decay; no significant decay was detected for any compound. Cell parameters were retrieved with SMART software and refined using SAINT software on all reflections.…”

Section: X-ray Structure Determinationsmentioning

confidence: 99%

“…One cation was constrained to standard angles and distances because its potential disorder could not be successfully modeled. (Et 4 N) 3 [5] was refined in space group P2 1 /m (11) with two acetonitrile and one water solvate molecules on the mirror plane and five methanol solvate molecules either disordered or residing on or across the mirror plane. (Et 4 N) 4 [6] was refined in space group P2 1 /m with seven acetonitrile solvate molecules, which were constrained to reasonable bond lengths and angles.…”

Section: X-ray Structure Determinationsmentioning

confidence: 99%

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Hydroxide-Promoted Core Conversions of Molybdenum−Iron−Sulfur Edge-Bridged Double Cubanes: Oxygen-Ligated Topological P^N Clusters

et al. 2007

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The occurence of a heteroatom X (C, N, or O) in the MoFe 7 S 9 X core of the iron-molybdenum cofactor of nitrogenase has encouraged synthetic attempts to prepare high nuclearity M-Fe-S-X clusters containing such atoms. We have previously shown that reaction of the edge-bridged double cubane [(Tp) 6 (μ 6 -S)] core topology very similar to the P N cluster of nitrogenase. The reaction system 1/Et 4 NOH in acetonitrile/methanol yields the P N -type cluster [(Tp) 2 Mo 2 Fe 6 S 9 (OMe) 2 (H 2 O)] 3− (5). The system 1/Me 3 SnOH/F − affords the oxo-bridged double P N -type cluster {[(Tp) 2 Mo 2 Fe 6 S 9 (μ 2 -O)] 2 } 5− (7), convertible to the oxidized cluster {[(Tp) 2 Mo 2 Fe 6 S 9 (μ 2 -O)] 2 } 4− (6), which is prepared independently from [(Tp) 2 Mo 2 Fe 6 S 9 F 2 (H 2 O)] 3− /(Bu 3 Sn) 2 O. In the preparations of 3-5 and 7, hydroxide liberates sulfide from 1 leading to the formation of P N -type clusters. Unlike reactions with HQ − , no oxygen atoms are integrated into the core structures of the products. However, the half-dimer composition [Mo 2 Fe 6 S 9 O] relates to the MoFe 7 S 9 consitution of the putative native cluster with X = O. (Tp = hydrotris(pyrazolyl) borate(1-)).

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Nitrogenase: Recent Advances

Andrade

Ribbe

et al. 2004

Handbook of Metalloproteins

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Nitrogenase catalyzes the reductive fixation of nitrogen from atmospheric N 2 for biological syntheses, and as such it constitutes the only enzyme known to be able to cleave the highly stable triple bond of the dinitrogen molecule. Structures are known of both component proteins of nitrogenase, the enzymatically active MoFe protein and its electron donor, the Fe protein. In spite of a wealth of biochemical and biophysical data on nitrogenase, the mechanistic details of its action remain poorly understood. This article provides an update on recent results in nitrogenase research, including the discovery of a central, light atom in the center of the FeMo cofactor, studies on substrate binding to the cofactor in mutant proteins, and novel aspects of complex formation between both component proteins. Particular emphasis is given to the significant progress made in understanding the biosynthesis of the complex metal clusters of the MoFe protein, the P‐cluster and the FeMo cofactor.

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Synthesis of a Molecular Mo₂Fe₆S₉ Cluster with the Topology of the P^N Cluster of Nitrogenase by Rearrangement of an Edge-Bridged Mo₂Fe₆S₈ Double Cubane

Cited by 107 publications

References 27 publications

P-cluster maturation on nitrogenase MoFe protein

P-cluster maturation on nitrogenase MoFe protein

Hydroxide-Promoted Core Conversions of Molybdenum−Iron−Sulfur Edge-Bridged Double Cubanes: Oxygen-Ligated Topological P^N Clusters

Nitrogenase: Recent Advances

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Synthesis of a Molecular Mo2Fe6S9 Cluster with the Topology of the PN Cluster of Nitrogenase by Rearrangement of an Edge-Bridged Mo2Fe6S8 Double Cubane

Cited by 107 publications

References 27 publications

P-cluster maturation on nitrogenase MoFe protein

P-cluster maturation on nitrogenase MoFe protein

Hydroxide-Promoted Core Conversions of Molybdenum−Iron−Sulfur Edge-Bridged Double Cubanes: Oxygen-Ligated Topological PN Clusters

Nitrogenase: Recent Advances

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Synthesis of a Molecular Mo₂Fe₆S₉ Cluster with the Topology of the P^N Cluster of Nitrogenase by Rearrangement of an Edge-Bridged Mo₂Fe₆S₈ Double Cubane

Hydroxide-Promoted Core Conversions of Molybdenum−Iron−Sulfur Edge-Bridged Double Cubanes: Oxygen-Ligated Topological P^N Clusters