Journal of Inorganic Biochemistry最新文献

{"title":"Biomimics of [FeFe]‑hydrogenases: Diiron aza- versus oxadiphenylpropanedithiolate complexes with mono- versus diphosphines","authors":"Pei-Hua Zhao,&nbsp;Yan Gao,&nbsp;Yu-Long Sun,&nbsp;Xing-Bin Jing,&nbsp;Diao-Yu Zhou","doi":"10.1016/j.jinorgbio.2025.112859","DOIUrl":"10.1016/j.jinorgbio.2025.112859","url":null,"abstract":"<div><div>To extensively devolep the bioinspired chemistry of [FeFe]‑hydrogenases, this study performs an insigt into the selective substitution of all‑carbonyl diiron aza- versus oxadiphenylpropanedithiolate precursors Fe₂(<em>μ</em>-Ph₂xdt)(CO)₆ (Ph₂xdt = Ph₂odt = (SCHPh)₂O for <strong>1</strong> and Ph₂adt^NH = (SCHPh)₂NH for <strong>2</strong>) by mono- versus diphosphines P(C₆H₄R-<em>p</em>)₃ (R = Me and Cl) and (Ph₂P)₂R′ (R′ = <em>cis</em>-CH=CH- for dppv and -CH₂CH₂- for dppe). With monophosphines, their monosubstituted diiron Ph₂odt complexes Fe₂(<em>μ</em>-Ph₂odt)(CO)₅){<em>κ</em>¹-P(C₆H₄R-<em>p</em>)₃} (R = Me for <strong>1a</strong> and Cl for <strong>1b</strong>) were obtained through the oxidative decarbonylating of <strong>1</strong> at room temperature in MeCN with Me₃NO·2H₂O; in contrast, analogous diiron Ph₂adt^NH complexes Fe₂(<em>μ</em>-Ph₂adt^NH)(CO)₅){<em>κ</em>¹-P(C₆H₄R-<em>p</em>)₃} (R = Me for <strong>2a</strong> and Cl for <strong>2b</strong>) were afforded via the photolytic decarbonlating of <strong>2</strong> under UV irradiation (365 nm) in toluene. With diphosphines, the dppv-chelated diiron Ph₂xdt complexes Fe₂(<em>μ</em>-Ph₂xdt)(CO)₄(<em>κ</em>²-dppv) (Ph₂xdt = Ph₂odt for <strong>1c</strong> and Ph₂adt^NH for <strong>2c</strong>) were prepared from the UV-irradiated decarbonylation of <strong>1</strong> or <strong>2</strong> in toluene; by contrast, the dppe-chelated diiron similar complexes Fe₂(<em>μ</em>-Ph₂xdt)(CO)₄(<em>κ</em>²-dppe) (Ph₂xdt = Ph₂odt for <strong>1d</strong> and Ph₂adt^NH for <strong>2d</strong>) were synthesized from the Me₃NO-assisted decarbonylation of <strong>1</strong> in room-temperature MeCN and that of <strong>2</strong> at refluxing toluene, respectively. The elemental analysis, FT-IR and NMR (¹H, ³¹P) spectroscopy are used for the full elucidation of the molecular structures of these new diiron complexes and X-ray crystallography is applied for further confirmation of <strong>1</strong>, <strong>2</strong> and <strong>1a</strong>, <strong>2b</strong>. The electrochemical properties of representative complexes <strong>1</strong>, <strong>1a</strong>, <strong>1c</strong> and <strong>2</strong>, <strong>2a</strong>, <strong>2c</strong> have been explored and compared with and without acetic acid (AcOH).</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"267 ","pages":"Article 112859"},"PeriodicalIF":3.8,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and characterization of porphyrin-based photosensitizing metalloproteins integrated with artificial metalloenzymes for photocatalytic hydrogen production","authors":"L.V. Opdam ,&nbsp;S.K. Goetzfried ,&nbsp;E. Polanco ,&nbsp;S. Bonnet ,&nbsp;A. Pandit","doi":"10.1016/j.jinorgbio.2025.112855","DOIUrl":"10.1016/j.jinorgbio.2025.112855","url":null,"abstract":"<div><div>Hydrogen is regarded as a promising alternative to fossil fuels. A desirable method of its generation is via photocatalysis, combining photosensitizers and hydrogen-evolution catalysts in the presence of an electron donor. Inspired by natural photosynthesis, we designed photosensitizing artificial metalloproteins (ArMs) and integrated them with ArM-based catalysts for photocatalytic hydrogen production from water. Metal porphyrins based on protoporphyrin IX (PPIX) were employed as they are naturally abundant and are effective both as photosensitizers and hydrogen-evolution catalysts. Photosensitizing proteins were created by binding zinc (Zn)PPIX or ruthenium (Ru)PPIX to the haem acquisition system A <em>from Pseudomonas aeruginosa</em> (HasAp). The photosensitizer ArMs were combined with cobalt (Co)PPIX-myoglobin (Mb) or free CoPPIX as hydrogen evolution catalysts. We found that free CoPPIX could replace ZnPPIX or RuPPIX in HasAp, forming CoPPIX-HasAp or RuPPIX-CoPPIX-HasAp complexes with enhanced stability compared to CoPPIX-Mb. Photocatalytic hydrogen production was achieved upon irradiation at 435 nm (ZnPPIX) or 385 nm (RuPPIX), using methyl viologen as an electron carrier and triethanolamine as an electron donor. The ZnPPIX-HasAp/CoPPIX-HasAp system remained intact and active for approximately 42 h, while Ru-based systems that were excited by UV light, exhibited signs of protein cleavage upon prolonged irradiation. These results demonstrate the potential of integrating porphyrin-based ArMs for photosensitization and hydrogen evolution, with HasAp providing a robust scaffold for sustained photocatalytic activity.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"267 ","pages":"Article 112855"},"PeriodicalIF":3.8,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Twenty years in metalloprotein bioinformatics: A short history of a long journey","authors":"Claudia Andreini","doi":"10.1016/j.jinorgbio.2025.112854","DOIUrl":"10.1016/j.jinorgbio.2025.112854","url":null,"abstract":"<div><div>The study of the structure and function of metalloproteins is a central subject of inorganic biochemistry. Starting from the 2000s, computational methods have flanked experimental research by exploiting the ever-increasing computing power and the huge amount of data produced by omics technologies. In this article, we retrace the major advancements that brought bioinformatics from being of minor relevance to being an essential tool for today's inorganic biochemists, focusing on the contributions coming from the Magnetic Resonance Center (CERM) of Florence, where we have been developing for twenty years methods and resources to investigate metalloproteins with computational approaches.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112854"},"PeriodicalIF":3.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antitumor activity of ruthenium(III) complexes with [N2O2]-tetradentate Schiff base ligands","authors":"Zdravka Petrova ,&nbsp;Teodora Mocanu ,&nbsp;Rossen Spasov ,&nbsp;Anamaria Hanganu ,&nbsp;Gabriela Marinescu ,&nbsp;Daniela C. Culita ,&nbsp;Radostina Alexandrova","doi":"10.1016/j.jinorgbio.2025.112853","DOIUrl":"10.1016/j.jinorgbio.2025.112853","url":null,"abstract":"<div><div>In this article, the antitumor and antiproliferative activity of three Ru(III) complexes, [Ru^III(Salen)(PPh₃)Cl] (<strong>RuSalen</strong>), [Ru^III(Salphen)(PPh₃)Cl] (<strong>RuSalphen</strong>), and [Ru^III(Salpn)(PPh₃)Cl] (<strong>RuSalpn</strong>) (H₂Salen, H₂Salphen and H₂Salpn are the Schiff bases obtained by the condensation between salicylaldehyde and ethylenediamine, 1,2-phenylenediamine, and 1,3-diaminopropanne, respectively) and their precursor, [Ru^II(PPh₃)₃Cl₂], were investigated against laboratory-cultured tumor cell lines: HT29 (human colorectal carcinoma), Saos-2 (human osteogenic sarcoma), HeLa (human cervical carcinoma), RST (rat transplantable sarcoma), and the non-tumor cell line Lep3 (embryonal human fibroblasts). It was found that all the cancer cell lines investigated were effectively dose-dependently inhibited in their growth by the Ru(III) complexes, while the non-tumor cell line Lep3 was the least affected by their cytotoxic effect. The Annexin V assay revealed that the Ru(III) complexes determined the occurrence of apoptosis in all cell lines tested, in a dose-dependent manner. <strong>RuSalpn</strong> exhibited the strongest ability to reduce tumor cell survival and proliferation, with efficacy that is either superior to or comparable to that of well-established clinical oncology agents such as cisplatin, oxaliplatin, epirubicin, and paclitaxel. The experiments revealed a cell-specific response, with varying degrees of sensitivity to the tested substances across different cell lines. <strong>RuSalpn</strong> demonstrated the strongest cytotoxic effect in the HT29 cell line, while <strong>RuSalen</strong>, <strong>RuSalphen</strong> showed the highest activity against RST cells. It was found that <strong>RuSalphen</strong> (≥7.0 μM) significantly inhibited cell migratory activity in the HT29 cell line, while in the RST cell line, <strong>RuSalen</strong> (≥37.6 μM), <strong>RuSalphen</strong> (≥14.0 μM), and <strong>RuSalpn</strong> (≥36.8 μM) demonstrated a strong inhibitory effect on cell migration.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112853"},"PeriodicalIF":3.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclometalated iridium(III)-lonidamine conjugates: Mitochondrial targeting and pyroptosis induction","authors":"Xing-Yun Lu ,&nbsp;Lin-Yuan Zhu ,&nbsp;Hou Zhu,&nbsp;Shao-Jun Huang,&nbsp;Yong-Sheng Yang,&nbsp;Chun-Rong Jiang,&nbsp;Rui-Rong Ye","doi":"10.1016/j.jinorgbio.2025.112852","DOIUrl":"10.1016/j.jinorgbio.2025.112852","url":null,"abstract":"<div><div>A series of cyclometalated Ir(III)-lonidamine (LND) complexes (<strong>Ir-LND-1–6</strong>) with the formula [Ir(C^N)₂bpy(4-CH₃–4’-CH₂OLND)](PF₆) (<strong>Ir-LND-1–3</strong>) and [Ir(C^N)₂bpy(4-CH₂OLND-4’-CH₂OLND)](PF₆) (<strong>Ir-LND-4–6</strong>) (C^<em>N</em> = 2-phenylpyridine (ppy, in <strong>Ir-LND-1</strong> and <strong>Ir-LND-4</strong>), 2-(2-thienyl) pyridine (thpy, in <strong>Ir-LND-2</strong> and <strong>Ir-LND-5</strong>) and 2-(2,4-difluorophenyl) pyridine (dfppy, in <strong>Ir-LND-3</strong> and <strong>Ir-LND-6</strong>)), were designed and synthesized. 3-(4,5-dimethylthiazol-2-yl)-2,5-biphenyltetrazolium bromide (MTT) assay data showed that the cytotoxicity of <strong>Ir-LND-1–3</strong> carry one LND moiety was superior to that of <strong>Ir-LND-4</strong>–<strong>6</strong> with two LND moieties. Therefore, we selected <strong>Ir-LND-1–3</strong> as model compounds to investigate the anti-tumor mechanism of the Ir(III)-LND system. The results showed that <strong>Ir-LND-1–3</strong> could inhibit cancer cell migration and colony formation. In addition, <strong>Ir-LND-1–3</strong> could penetrate into HeLa cells and localized to mitochondria, further disrupting mitochondrial membrane potential (MMP), increasing intracellular reactive oxygen species (ROS), and reducing intracellular adenosine triphosphate (ATP). Further exploration of anti-tumor mechanisms showed that pyroptosis was the main mode of <strong>Ir-LND-1–3</strong> induced cell death, manifested as membrane perforation and swelling, activation of caspase-3 and cleavage of Gasdermin E (GSDME), as well as release of lactic dehydrogenase (LDH) and ATP. The pyroptosis induced by <strong>Ir-LND-1–3</strong> also initiated immunogenic cell death (ICD) by triggering the release of calreticulin (CRT) and high mobility group protein b1 (HMGB1) on the cell surface.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112852"},"PeriodicalIF":3.8,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heme and immunity: The heme oxygenase dichotomy","authors":"Melissa Perry ,&nbsp;Iqbal Hamza","doi":"10.1016/j.jinorgbio.2025.112844","DOIUrl":"10.1016/j.jinorgbio.2025.112844","url":null,"abstract":"<div><div>Heme, an iron containing organic ring, is required for a diverse range of biological processes across all forms of life. Although this nutrient is essential, its pro-inflammatory and cytotoxic properties can lead to cellular damage. Heme oxygenase 1 (HO-1) is an endoplasmic reticulum (ER)-anchored enzyme that degrades heme, releasing equimolar amounts of carbon monoxide (CO), biliverdin (BV), and iron. The induction of HO-1 by heme presents an interesting dichotomy in the cell: CO and BV possess anti-inflammatory and antioxidant properties while free iron can be detrimental as it can generate hydroxyl radicals through the Fenton reaction. The heme/HO-1 axis is tightly regulated, and can influence cell fate, local tissue environments, and disease outcomes during pathogen infection. In this review we explore the role of heme during macrophage polarization and its ability to act as an immune activator while also examining the contribution of HO-1 and heme during infections with intracellular and extracellular pathogens. We highlight work from the emerging field of nutritional immunity of heme and iron, and how the substrates and byproducts of heme metabolism via HO-1 can be beneficial to the host or the pathogen depending on the context.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"267 ","pages":"Article 112844"},"PeriodicalIF":3.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RP-HPLC reveals the L-cysteine induced degradation of phenylmercuric acetate","authors":"Mahamad Ihsan Attia,&nbsp;Jürgen Gailer","doi":"10.1016/j.jinorgbio.2025.112851","DOIUrl":"10.1016/j.jinorgbio.2025.112851","url":null,"abstract":"","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112851"},"PeriodicalIF":3.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel silver(I) complexes with fenamates: Insights into synthesis, spectral characterization, and bioactivity","authors":"Lidia Zapała ,&nbsp;Ewa Ciszkowicz ,&nbsp;Małgorzata Kosińska-Pezda ,&nbsp;Urszula Maciołek ,&nbsp;Anna E. Kozioł ,&nbsp;Anna Miłoś ,&nbsp;Elżbieta Woźnicka ,&nbsp;Aleksandra Bocian ,&nbsp;Wojciech Zapała ,&nbsp;Katarzyna Rydel-Ciszek ,&nbsp;Maria Grazia Perrone","doi":"10.1016/j.jinorgbio.2025.112846","DOIUrl":"10.1016/j.jinorgbio.2025.112846","url":null,"abstract":"<div><div>Six new Ag(I) ions complexes with <em>N</em>-phenylanthranilic, mefenamic, and niflumic acids have been synthesized. Three of them are binary complexes with the [Ag(L)] formula (where L represents <em>N-</em>phenylanthranilate (nfa), mefenamate (mfa), or niflumate (nif) ions), and the other three complexes are ternary with the formula [Ag(L)(phen)₂]⋅nH₂O (where phen - 1,10-phenanthroline). The complexes were characterized by elemental analysis, differential scanning calorimetry (DSC), X-ray fluorescence, powder X-ray diffraction, and single-crystal X-ray structure analysis. <strong>Additionally,</strong> techniques such as ESI-MS spectrometry, ¹H NMR, UV–Vis, and FTIR spectroscopy were employed. The X-ray crystallography showed that in the solid [Ag(nif)] complex, the cation showed an unusual structure with coordination number 5, i.e. AgO₃NC. The silver cation interacts with three niflumate anions, forming a two-dimensional coordination polymer. Complexes have potential antibacterial efficacy with varied minimum inhibitory concentration values (MIC) between 45.96 and 800 μM against multidrug-resistant <em>Pseudomonas aeruginosa</em>. Antibacterial combination therapy of Ag(I) complexes with chloramphenicol (CHL) and kanamycin (KAN) showed a very strong synergistic impact against <em>P. aeruginosa</em> with no cytotoxic effect on normal human fibroblasts. Complexes [Ag(nif)] and [Ag(nfa)] inhibit protein denaturation, bind to BSA via <strong>static quenching</strong> (k_q = 0.65–1.08 × 10¹³ M⁻¹ s⁻¹). Furthermore, the formation of these complexes enhances the penetration of the drug across <strong>human membrane monolayers</strong>, which could improve bioavailability and therapeutic potential. The [Ag(nif)] complex demonstrates significant potential for topical dermal application due to its antimicrobial and anti-inflammatory properties. Notably, among all complexes evaluated, it displays the lowest BA/AB ratio (5.41), facilitating the most efficient transdermal permeation.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112846"},"PeriodicalIF":3.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Silver(I) complexes containing bioactive salicylic acid derivatives: Synthesis, characterization, antibacterial activity, and their underlying mechanism","authors":"Chongyang Wu ,&nbsp;Yanni Shan ,&nbsp;Jingming Luo ,&nbsp;Xudong Fan ,&nbsp;Ren Zheng ,&nbsp;Suhang Guo ,&nbsp;Xinjun Cai","doi":"10.1016/j.jinorgbio.2025.112845","DOIUrl":"10.1016/j.jinorgbio.2025.112845","url":null,"abstract":"<div><div>Recognizing that silver-metallodrugs are a potential source of novel anti-infective therapeutic agents, this work adopts the complexation of biologically active salicylic acid derivatives with inherently antibacterial silver(I) ions as a strategy for developing new antibacterial agents. The synthesized silver(I) complexes were characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis. The crystallographic results indicate that the silver(I) ion in complexes [Ag(imH)₂](SalH) (<strong>1</strong>) and [Ag(imH)₂](DiSalH)·H₂O (<strong>2</strong>) only coordinates with the imidazole nitrogen atom, while the 4-aminosalicylic acid in complex [Ag(imH)₂(AmSalH)]·H₂O (<strong>3</strong>) additionally coordinate with the silver(I) ion through the amino nitrogen atom. Salicylic acid molecules play an important role in the construction of the three-dimensional network structure through weak interactions. In addition, thermogravimetric analysis, stability, and silver(I) ion release experiments indicate that these complexes have good stability and slow ion release rates. Cell toxicity and antibacterial tests were conducted on selected cell lines and microorganisms using complexes <strong>1–3</strong>, and compared with silver(I) salts, organic ligands, and antibiotic. All complexes exhibit better biocompatibility and certain anti-tumor selectivity than silver(I) salts. From the perspective of microbial toxicity, complexes <strong>1–3</strong> all have significant inhibitory effects on three bacteria strains, with complex <strong>1</strong> having the strongest antibacterial activity, exhibiting 4–6 times higher activity against certain strains than AgNO₃ and chloramphenicol. Mechanism studies have shown that cell wall perforation and imbalance of intracellular ROS levels may be possible reasons for silver(I) complexes induced bacterial cell death. The biofilm removal experiment further proves the potential use of silver(I) complexes <strong>1–3</strong> in the treatment of bacterial infections.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112845"},"PeriodicalIF":3.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactions between heme and G-quadruplex DNA involve the oxygen of guanine","authors":"Tapiwa Chiura,&nbsp;Minh N. Pham,&nbsp;Dana A. Baum,&nbsp;Piotr J. Mak","doi":"10.1016/j.jinorgbio.2025.112843","DOIUrl":"10.1016/j.jinorgbio.2025.112843","url":null,"abstract":"<div><div>Guanine quadruplexes are non-canonical DNA structures with various functions including transcription and translation regulation and telomere protection. These structures are known to bind the heme prosthetic group, resulting in heme-bound G-quadruplexes (heme-G4) that exhibit enhanced peroxidase activity and act as promising biocatalysts. The structure of the heme-G4, specifically how the DNA scaffold interacts with the heme iron, is key in understanding the catalytic mechanism of these DNAzymes. In heme proteins, the nature of a heme axial ligand plays an essential role in manipulating the inherent reactivity of the heme prosthetic group. Several proposals regarding the heme axial ligand in the heme-G4 complexes have been previously presented, including nitrogen or oxygen atoms of the guanine base or a water molecule sandwiched between the heme macrocycle and the DNA quadruplex. Despite numerous studies, no convincing experimental evidence has yet been provided as to the nature of the key proximal ligand. In this work, we present extensive electronic absorption and resonance Raman spectroscopic studies of ferric and ferrous heme-G4 complexes, including their ligated forms. Our studies provide experimental evidence that the oxygen atom of the guanine base acts as an axial ligand supported by detection of the <em>ν</em>(Fe-O_G) stretching mode at 563 cm⁻¹ in the spectra of ferric heme-G4. These results provide structural data that can help understand the mechanistic principles behind the observed enhanced peroxidase activity of heme-G4 quadruplexes and aid in design of advanced biocatalysts.</div></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"266 ","pages":"Article 112843"},"PeriodicalIF":3.8,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}