Journal of Biological Inorganic Chemistry最新文献

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Electrochemical characterization of C. pasteurianum hydrogenase II and three site-directed variants: catalysis and inhibition 巴氏杆菌氢化酶II和三个位点变异的电化学表征:催化和抑制。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-08-02 DOI: 10.1007/s00775-026-02169-6
Miriam Malagnini, Andrea Fasano, Aurore Jacq-Bailly, Luzie H. I. Hardt, Theresa Wenig, Sophie Webb, Ross D. Milton, Vincent Fourmond, Christophe Léger
{"title":"Electrochemical characterization of C. pasteurianum hydrogenase II and three site-directed variants: catalysis and inhibition","authors":"Miriam Malagnini,&nbsp;Andrea Fasano,&nbsp;Aurore Jacq-Bailly,&nbsp;Luzie H. I. Hardt,&nbsp;Theresa Wenig,&nbsp;Sophie Webb,&nbsp;Ross D. Milton,&nbsp;Vincent Fourmond,&nbsp;Christophe Léger","doi":"10.1007/s00775-026-02169-6","DOIUrl":"10.1007/s00775-026-02169-6","url":null,"abstract":"<div><p>Certain <i>Clostridium pasteurianum</i> strains encode up to four FeFe-hydrogenases, which are homologous (identity &gt; 20%) but can be readily distinguished by their number of residues (450–550), the nature and number of accessory iron-sulfur clusters (up to four), and the composition of the so-called P1 motif (TSCCP in <i>CpI</i> and <i>CpII</i>, TSCCCP in <i>CpIII</i>, or NSCCP in <i>CpIV</i>). <i>CpI</i> is one of the most extensively characterized FeFe-hydrogenases; here we compare it with <i>CpII</i> using protein film electrochemistry, the technique invented and popularised by Fraser Armstrong in Oxford. In this approach the enzyme is wired to an electrode and then interrogated to obtain information on their catalytic responses and reactions with the inhibitors. With the aim of elucidating the relation between structure and function within the FeFe-hydrogenase family, we also examined the effects of replacing three <i>CpII</i> residues with the corresponding residues from <i>CpI</i>: S99A, near the active-site dinuclear cluster; T377A, between the cubane and the proximal cluster; and S73A, near the distal cluster. Small effects are observed on the catalytic bias (S99A) and the Michaelis constant for H₂ (S99A), but not on the irreversibility of the catalytic response of <i>CpII</i>. The most significant changes concern the reaction with O₂: unlike <i>CpI</i>, <i>CpII</i> reacts fully irreversibly with O₂; the T377A and S99A mutations significantly slow this reaction, whereas the S73A mutation makes it more reversible. These findings have far-reaching implications for ongoing research aimed at understanding why homologous hydrogenases exhibit distinct catalytic properties, by suggesting that these differences likely arise from a combination of small changes rather than a single underlying cause.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 6","pages":"537 - 551"},"PeriodicalIF":2.8,"publicationDate":"2026-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148652755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Correction: [FeFe] hydrogenases with modified azadithiolate bridgeheads serve as unidirectional hydrogen oxidation catalysts 修正:偶氮硫酸酯桥头修饰的[FeFe]氢化酶作为单向氢氧化催化剂。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-31 DOI: 10.1007/s00775-026-02163-y
Manon T. Lachmann, James A. Birrell, Simone Morra, Patricia Rodríguez-Maciá
{"title":"Correction: [FeFe] hydrogenases with modified azadithiolate bridgeheads serve as unidirectional hydrogen oxidation catalysts","authors":"Manon T. Lachmann,&nbsp;James A. Birrell,&nbsp;Simone Morra,&nbsp;Patricia Rodríguez-Maciá","doi":"10.1007/s00775-026-02163-y","DOIUrl":"10.1007/s00775-026-02163-y","url":null,"abstract":"","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"447 - 449"},"PeriodicalIF":2.8,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00775-026-02163-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148629163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Insights into the pH-dependent reactivity and substrate induced active-site reorganization of the non- heme iron enzyme CthEgtB 非血红素铁酶CthEgtB的ph依赖性反应性和底物诱导的活性位点重组的见解。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-30 DOI: 10.1007/s00775-026-02167-8
Kassidy W. Rodriguez, Phuong Hong Ngoc Tao, Kiran Kurmi, Katlyn K. Meier
{"title":"Insights into the pH-dependent reactivity and substrate induced active-site reorganization of the non- heme iron enzyme CthEgtB","authors":"Kassidy W. Rodriguez,&nbsp;Phuong Hong Ngoc Tao,&nbsp;Kiran Kurmi,&nbsp;Katlyn K. Meier","doi":"10.1007/s00775-026-02167-8","DOIUrl":"10.1007/s00775-026-02167-8","url":null,"abstract":"<div><p>Ergothioneine biosynthesis relies on the non-heme Fe(II) sulfoxide synthase EgtB, which couples O₂ activation to stereoselective C-S bond formation between trimethylhistidine (TMH; hercynine) and L-cysteine (L-Cys). Here, we utilize circular dichroism (CD), differential scanning fluorescence, light scattering, and stopped-flow spectroscopy to define how metal loading, substrate addition, oxygen availability, and pH shape the active site and catalysis of tetrameric EgtB from <i>Chloracidobacterium thermophilum</i> (<i>Cth</i>). Far-UV CD and thermal unfolding data confirm <i>Cth</i>EgtB’s stable, predominantly alpha helical secondary structure under all conditions studied, while Fe(II) and sequential substrate binding help to stabilize the enzyme. Visible CD demonstrates a distinct ligand-field reorganization upon sequential addition of Fe(II), L-Cys, and TMH to apo-<i>Cth</i>EgtB. Subsequent exposure to O₂ results in a shift of the ligand-field and charge-transfer features with associated appearance of a high energy feature consistent with the formation of sulfoxide product. The pH- and temperature-dependent kinetics of the reaction were monitored via stopped-flow absorption spectroscopy and show max activity at pH 7.0 and rates that scale with O₂ concentration, indicating tightly coupled O₂ binding and activation. Mass spectrometry confirms oxygen dependent formation of the hercynylcysteine sulfoxide product. Finally, we provide clear evidence that retention of a 6x N-terminal histidine-tag decreases the activity and stability of <i>Cth</i>EgtB, confirming that tagged constructs do not fully reproduce native behavior. Together, these results support a unified mechanism in which Fe(II), substrate binding, protonation environment around the active site, and O₂ availability poise the <i>Cth</i>EgtB active site for efficient oxygen activation and sulfoxide formation.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 6","pages":"507 - 519"},"PeriodicalIF":2.8,"publicationDate":"2026-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00775-026-02167-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lysine or histidine? examining the role of the proximal ligand at the active heme center of cytochrome c nitrite reductase 赖氨酸还是组氨酸?探讨近端配体在细胞色素c亚硝酸盐还原酶活性血红素中心的作用。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-28 DOI: 10.1007/s00775-026-02165-w
Bianca Hermann, Marc Rudolf, Albrecht Messerschmidt, Jörg Simon, Oliver Einsle, Peter M.H. Kroneck
{"title":"Lysine or histidine? examining the role of the proximal ligand at the active heme center of cytochrome c nitrite reductase","authors":"Bianca Hermann,&nbsp;Marc Rudolf,&nbsp;Albrecht Messerschmidt,&nbsp;Jörg Simon,&nbsp;Oliver Einsle,&nbsp;Peter M.H. Kroneck","doi":"10.1007/s00775-026-02165-w","DOIUrl":"10.1007/s00775-026-02165-w","url":null,"abstract":"<div><p>The identity of the proximal ligand of its catalytic heme 1 center - lysine or histidine - may directly affect how efficiently pentaheme cytochrome <i>c</i> nitrite reductase catalyzes the six-electron reduction of nitrite (NO<sub>2</sub><sup>−</sup>) to ammonium (NH<sub>4</sub><sup>+</sup>) and may also alter substrate specificity. This reaction is part of the pathway of dissimilatory nitrate reduction to ammonium, which competes with denitrification and avoids the formation of unreactive dinitrogen (N<sub>2</sub>). In this study, we compare the biochemical properties and structures of cytochrome <i>c</i> nitrite reductase from <i>Campylobacter jejuni</i> with those of the enzyme from <i>Wolinella succinogenes</i> and examine its Lys134His variant. Notably, both the <i>Campylobacter</i> nitrite reductase and the Lys134His variant possess a catalytic heme 1 center coordinated by histidine as the proximal ligand, whereas the native <i>Wolinella</i> enzyme is coordinated by lysine. Despite this difference, both enzymes catalyze the reduction of NO<sub>2</sub><sup>−</sup> to NH<sub>4</sub><sup>+</sup> with high specific activities. To enable biochemical and structural characterization of these enzymes, we developed optimized protocols for protein expression and purification. The data we present allow, for the first time, a direct analysis of the influence of histidine or lysine as the proximal nitrogen ligand at the catalytic heme 1 center of pentaheme cytochrome <i>c</i> nitrite reductase within otherwise similar protein backgrounds.</p></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"317 - 328"},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00775-026-02165-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148597430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Molecular strategies for flux control in an electron bifurcation protein 电子分岔蛋白通量控制的分子策略。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-23 DOI: 10.1007/s00775-026-02164-x
Niven Singh, Kiriko Terai, David Beratan
{"title":"Molecular strategies for flux control in an electron bifurcation protein","authors":"Niven Singh,&nbsp;Kiriko Terai,&nbsp;David Beratan","doi":"10.1007/s00775-026-02164-x","DOIUrl":"10.1007/s00775-026-02164-x","url":null,"abstract":"<p>Electron-bifurcating flavoproteins split electron pairs and deposit them in spatially separated electron-acceptor pools. Just how electron-transfer networks regulate steady-state electron-bifurcation (EB) fluxes and efficiencies remains unclear. We model the steady-state kinetics of electron-bifurcation in NADH-dependent ferredoxin–NADP<span>(^+)</span> oxidoreductase I (Nfn1), based on the protein’s structure and electrochemistry. We use a many-particle master-equation to simulate the steady-state kinetics. The analysis identifies control points that are defined by electronic couplings between cofactors, and we explore how the interactions between cofactors influence EB function. We find that couplings on the low-potential branch dictate EB efficiency and the onset of short-circuiting, while the couplings on the high-potential branch determine the magnitude of the steady-state bifurcation flux in Nfn1. Analysis of interactions using the tunneling pathway model indicates that pathway connectivity between the bifurcating donor and its high-potential acceptor is weak for its distance; this decoupling may serve to further suppress short-circuiting and favor productive electron flow.</p>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"329 - 338"},"PeriodicalIF":2.8,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148560270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Genetic dissection of formate hydrogenlyase-2 function: a metalloenzyme involved in bacterial hydrogen production 甲酸氢解酶-2功能的遗传解剖:一种参与细菌产氢的金属酶。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-23 DOI: 10.1007/s00775-026-02168-7
Thomas C.P. Reed, Alexander J. Finney, Magali Roger, Frank Sargent
{"title":"Genetic dissection of formate hydrogenlyase-2 function: a metalloenzyme involved in bacterial hydrogen production","authors":"Thomas C.P. Reed,&nbsp;Alexander J. Finney,&nbsp;Magali Roger,&nbsp;Frank Sargent","doi":"10.1007/s00775-026-02168-7","DOIUrl":"10.1007/s00775-026-02168-7","url":null,"abstract":"<div><p>Formate hydrogenlyases are metalloenzymes that can either produce molecular hydrogen gas or use H<sub>2</sub> to convert carbon dioxide to formic acid, thus potentially contributing doubly to a sustainable energy future. The structure of formate hydrogenlyase reveals a membrane-bound redox enzyme that shares a common ancestor with the mitochondrial complex I (NADH dehydrogenase). As such, formate hydrogenlyase falls into a category of so‐called ‘complex‐I‐like’ enzymes, that are found in bacteria, archaea and eukaryotic organelles. They share a common core structure of a membrane arm (most likely involved in proton or ion translocation) and a peripheral arm containing metal cofactors and involved in electron transfer. In this work, we clone a gene cluster from <i>Pectobacterium atrosepticum</i> encoding formate hydrogenlyase-2 (FHL-2). A bank of <i>Escherichia coli</i> host strains, themselves devoid of various combinations of native formate hydrogenlyase genes, are employed to characterise FHL-2. We demonstrate that <i>P. atrosepticum</i> FHL-2 is active in an <i>E. coli</i> host in that it can generate H<sub>2</sub> under fermentative growth conditions. Unlike native <i>E. coli</i> formate hydrogenlyase-1 (FHL-1), recombinant <i>P. atrosepticum</i> FHL-2 cannot perform the reverse reaction and generate formic acid from H<sub>2</sub> and CO<sub>2</sub>. By testing different combinations of genes by taking an in vivo cross-complementation approach we conclude that the extended membrane arm exhibited by FHL-2 is a major factor in controlling directionality of the enzyme.</p></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 6","pages":"521 - 535"},"PeriodicalIF":2.8,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00775-026-02168-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148560443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Amino acid mediated oxidative activation of multi-walled carbon nanotubes to introduce reversible proton-coupled electron transfer species 氨基酸介导的多壁碳纳米管氧化活化引入可逆质子偶联电子转移种。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-20 DOI: 10.1007/s00775-026-02161-0
Ella Kathryn Reid, Nicholas Garland, Nicholas David James Yates, Alison Parkin
{"title":"Amino acid mediated oxidative activation of multi-walled carbon nanotubes to introduce reversible proton-coupled electron transfer species","authors":"Ella Kathryn Reid,&nbsp;Nicholas Garland,&nbsp;Nicholas David James Yates,&nbsp;Alison Parkin","doi":"10.1007/s00775-026-02161-0","DOIUrl":"10.1007/s00775-026-02161-0","url":null,"abstract":"<div><p>Protein and enzyme film electrochemistry is a powerful technique which enables the energetics and kinetics of biological electron transfer processes to be quantified. One of the major challenges is finding a suitable electrode surface upon which a redox active protein or enzyme can be adsorbed in an electroactive configuration. Multi-walled carbon nanotubes (MWCNTs) have been a useful class of electrode modifiers which facilitate electroactive protein adsorption and provide a substantial increase in electrode surface area. MWCNTs are therefore commonly used in bioelectrochemical studies, with applications in analytical electrochemistry and electrochemical sensing. Herein, we report the effect of electrochemical oxidation on a MWCNT-functionalised glassy carbon electrode in the presence of adsorbed protein. Previously uncharacterised redox functionalities are introduced by sweeping to oxidising potentials (&gt; 0.8 V vs. SHE), with two reversible electron transfer signals subsequently appearing with midpoints of 80 and 390 mV at pH 7.0. This redox activity is hypothesised to be a result of the irreversible oxidation of the MWCNT-protein system resulting in the introduction of species capable of performing fast, reversible electron transfer.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"379 - 393"},"PeriodicalIF":2.8,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148519639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Redox implications of oxygen binding in hemoglobin and myoglobin: Thermodynamics of the (Fe3+/Fe2+) oxidation-reduction of heme-bound fluoride complexes versus fluoride binding 血红蛋白和肌红蛋白中氧结合的氧化还原意义:血红素结合氟化物复合物(Fe3+/Fe2+)氧化还原与氟化物结合的热力学
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-17 DOI: 10.1007/s00775-026-02159-8
Kayla Flanders, Annie Mathew, Mary Lockwood, Ashley Frankenfield, David Deysher, Kimberly Wodzanowski, Tanaka Mada, Thomas Nagle, Jose Cerda
{"title":"Redox implications of oxygen binding in hemoglobin and myoglobin: Thermodynamics of the (Fe3+/Fe2+) oxidation-reduction of heme-bound fluoride complexes versus fluoride binding","authors":"Kayla Flanders,&nbsp;Annie Mathew,&nbsp;Mary Lockwood,&nbsp;Ashley Frankenfield,&nbsp;David Deysher,&nbsp;Kimberly Wodzanowski,&nbsp;Tanaka Mada,&nbsp;Thomas Nagle,&nbsp;Jose Cerda","doi":"10.1007/s00775-026-02159-8","DOIUrl":"10.1007/s00775-026-02159-8","url":null,"abstract":"<div><p>In this study, the thermodynamics of the one-electron (Fe<sup>2+</sup>/Fe<sup>3+</sup>) oxidation-reduction of the heme-bound fluoride complexes of adult hemoglobin (Hb-F) and horse heart myoglobin (Mb-F) were addressed to interpret the molecular changes these proteins undergo during the redox reactions. We measured the enthalpy (Δ<i>H</i><sup>o’</sup>) and entropy (Δ<i>S</i><sup>o’</sup>) of these reactions at pH 5 and pH 7, and also for the oxidation-reduction reactions of the metaquo complexes and for fluoride binding. The temperature dependence of the reduction potentials (<i>E</i><sub>m</sub>) of Hb-F and Mb-F showed two redox pathways with distinct thermodynamic properties in the 5 to 45 °C temperature range, but only at pH 5. The <i>E</i><sub>m</sub>-<i>T</i> plots of Hb-F and Mb-F were complementary to each other, with opposing signs in their Δ<i>H</i><sup>o’</sup> and Δ<i>S</i><sup>o’</sup>. The redox reactions of the metaquo heme complexes and the heme-bound fluoride complexes (at pH 7) show no evidence of a bifurcated redox pathway. Given the similarities of the heme-ligand structures of oxy- and fluoride-bound complexes and comparable thermodynamics between oxidation and oxygen binding equilibrium, we theorize that one of the thermodynamic pathways is for stabilization of the heme-bound fluoride complex upon the redox change and the other is associated to a redox pathway that stabilizes the heme ferrous state, a route presumably associated to the unligated heme ferric-to-ferrous equilibrium. The serendipitous mixing of these redox pathways in the heme-bound fluoride complexes highlights the specificity of the heme proteins for oxygen binding and the possible use of these pathways for their respective physiological roles of storage and transport. The thermodynamics of the redox reactions of the heme-bound fluoride complexes of hemoglobin and myoglobin exhibit properties similar to those of their oxygen binding equilibria, which govern transport and oxygen storage.</p><h3>Graphical Abstract</h3><p>The thermodynamics of the redox reactions of the heme-bound fluoride complexes of hemoglobin and myoglobin exhibit properties similar to those of their oxygen binding equilibria, which govern transport and oxygen storage.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"359 - 378"},"PeriodicalIF":2.8,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148468177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Geometry, spin coupling, and dielectric control of redox potentials in [4Fe–4S] Clusters [4Fe-4S]簇中氧化还原电位的几何、自旋耦合和介电控制。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-16 DOI: 10.1007/s00775-026-02151-2
Peter S. Rice, Bruno Jacob, Khushbu Agarwal, Marcel D. Baer, Simone Raugei
{"title":"Geometry, spin coupling, and dielectric control of redox potentials in [4Fe–4S] Clusters","authors":"Peter S. Rice,&nbsp;Bruno Jacob,&nbsp;Khushbu Agarwal,&nbsp;Marcel D. Baer,&nbsp;Simone Raugei","doi":"10.1007/s00775-026-02151-2","DOIUrl":"10.1007/s00775-026-02151-2","url":null,"abstract":"<div><p>Iron–sulfur (Fe–S) clusters are common biological cofactors that facilitate vital redox reactions. Despite extensive research, the molecular basis of redox potential tuning in ferredoxin-like proteins remains an active area of debate. In this study, we combine statistical analysis of over one thousand [4Fe–4S]-containing protein structures from the Protein Data Bank (PDB) with broken-symmetry and extended broken-symmetry density functional theory to examine how cysteine ligand orientations and environmental screening affect redox properties of the clusters. We identified five main ligand configurations, three of which are predominant in natural structures. Among these, the adiabatic electron affinity differs by less than 0.1 V, indicating that, while geometry plays a secondary role, it allows localized fine-tuning of redox properties. In contrast, electrostatic and solvation effects primarily determine the overall potential range.</p></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"339 - 350"},"PeriodicalIF":2.8,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148468189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
EPR characterization of a metal-binding site in RquA RquA中一个金属结合位点的EPR表征。
IF 2.8 3区 化学
Journal of Biological Inorganic Chemistry Pub Date : 2026-07-14 DOI: 10.1007/s00775-026-02160-1
Rachelle K. Stowell, Trilok Neupane, Kristian C. Mankiller, Tanner L. Manning, Lily N. Boercker, Charlotte V. DiGaetano, Lauren R. Gotshall, Maegan N. Burke, Andrew Ozarowski, Eric E. Ross, David N. Langelaan, Jennifer N. Shepherd, Stefan Stoll
{"title":"EPR characterization of a metal-binding site in RquA","authors":"Rachelle K. Stowell,&nbsp;Trilok Neupane,&nbsp;Kristian C. Mankiller,&nbsp;Tanner L. Manning,&nbsp;Lily N. Boercker,&nbsp;Charlotte V. DiGaetano,&nbsp;Lauren R. Gotshall,&nbsp;Maegan N. Burke,&nbsp;Andrew Ozarowski,&nbsp;Eric E. Ross,&nbsp;David N. Langelaan,&nbsp;Jennifer N. Shepherd,&nbsp;Stefan Stoll","doi":"10.1007/s00775-026-02160-1","DOIUrl":"10.1007/s00775-026-02160-1","url":null,"abstract":"<div><p>Rhodoquinone (RQ) is a crucial electron carrier involved in anaerobic metabolism across select bacteria, protists, and animal species. Its biosynthesis is catalyzed by the rhodoquinone biosynthesis enzyme (RquA), a methyltransferase-like enzyme that uses <i>S</i>-adenosyl-<i>L</i>-methionine to transfer an amino group, converting ubiquinone (UQ) into RQ. The activity of RquA in vitro is enhanced by the presence of divalent metal cations. To probe the metal dependence of RquA, we characterized its interactions with Mn(II), Co(II), and Zn(II). We found that these metal cations bind to RquA with a 1:1 stoichiometry and that Mn(II) and Co(II) exhibited sub-micromolar binding affinities to RquA. Using Mn(II) as a spectroscopic probe, continuous‑wave electron paramagnetic resonance (EPR) revealed a single Mn(II) species with zero‑field splitting parameters |<i>D|</i> = 540(30) MHz and <i>E/D</i> = 0.30(3). Pulse EPR experiments on natural‑abundance and <sup>15</sup>N‑labeled samples further identified a weakly‑to‑moderately coupled nitrogen ligand, with an isotropic hyperfine coupling constant |<i>a</i><sub>iso</sub>(<sup>15</sup>N)| = 2.7(1) MHz. Integrating these data with an AlphaFold3‑derived structural model, we propose a putative binding site for the catalytically required divalent metal cation, providing new insight into the structural basis of RquA function.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":603,"journal":{"name":"Journal of Biological Inorganic Chemistry","volume":"31 5","pages":"409 - 420"},"PeriodicalIF":2.8,"publicationDate":"2026-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148434749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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