Journal of Inorganic Biochemistry最新文献

{"title":"Organotin(IV) complexes derived from 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone) as prospective anti-proliferative agents: Synthesis, characterization, structures and in vitro anticancer activity","authors":"Tushar S. Basu Baul ,&nbsp;Bietlaichhai Hlychho ,&nbsp;Siddhartha Das Pramanik ,&nbsp;Antonin Lyčka ,&nbsp;Partha Roy ,&nbsp;Abdallah G. Mahmoud ,&nbsp;M. Fátima C. Guedes da Silva","doi":"10.1016/j.jinorgbio.2024.112693","DOIUrl":"10.1016/j.jinorgbio.2024.112693","url":null,"abstract":"<div><p>Six organotin(IV) complexes, <em>viz.</em>, [Me₂Sn(L)] (<strong>1</strong>), [<em>n</em>-Bu₂Sn(L)] (<strong>2</strong>), [<em>n</em>-Oct₂Sn(L)] (<strong>3</strong>), [Bz₂Sn(L)]·0.5C₇H₈ (<strong>4</strong>), [<em>n</em>-BuSn(L)Cl] (<strong>5</strong>), and [PhSn(L)Cl] (<strong>6</strong>), were synthesized using a 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone), <strong>H</strong>_{<strong>2</strong>}<strong>L</strong>. Compounds were characterized by Fourier transform infrared (FT-IR), High-resolution mass spectrometry (HRMS), and solutions Fourier transform nuclear magnetic resonance (FT-NMR) spectroscopies. The structures <strong>1</strong>–<strong>6</strong> were established by single-crystal X-ray diffraction (SC-XRD) analysis. Diffraction results evidenced that complexes <strong>1–6</strong> were seven-coordinated mononuclear species with the equatorial plane comprising the pentagonal N₃O₂ chelate ring of the doubly deprotonated L and two axial ligands, either R (R = Me, <em>n</em>-Bu, <em>n</em>-Oct, Bz) or R (<em>n</em>-Bu or Ph) and Cl ligands. Additionally, the photophysical properties were examined due to the enhanced conjugation and rigidity of the molecules while thermogravimetric analysis was carried out to evaluate the thermal stabilities of compounds. The anti-proliferative activity of the complexes <strong>1</strong>–<strong>6</strong> was tested against prostate cancer cells (DU-145) and normal human embryonic kidney cells (HEK-293). Among the compounds, dibutyltin compound <strong>2</strong> exhibited increased anti-proliferative activity, with an IC₅₀ value of 6.16 ± 1.56 μM. The investigation of its mechanism of action involves using AO/EB (acridine orange/ethidium bromide) and ROS (reactive oxygen species) generation assays. This likely detects apoptotic morphological alterations in the nucleus of the cells, with ROS generation ultimately leading to apoptosis and cell death. The superior activity of <strong>2</strong> may be attributed to the C···H contacts and respective higher <em>d</em>_<em>e</em> outside and <em>d</em>_<em>i</em> inside distances from the Hirshfeld surface. Thus, these compounds could be a promising alternative to classical chemotherapy agents.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"261 ","pages":"Article 112693"},"PeriodicalIF":3.8,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088001","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":"Kinetic and structural analysis of redox-reversible artificial imine reductases","authors":"Alex H. Miller ,&nbsp;Ingrid B.S. Martins ,&nbsp;Elena V. Blagova ,&nbsp;Keith S. Wilson ,&nbsp;Anne-K. Duhme-Klair","doi":"10.1016/j.jinorgbio.2024.112691","DOIUrl":"10.1016/j.jinorgbio.2024.112691","url":null,"abstract":"<div><p>Three artificial imine reductases, constructed <em>via</em> supramolecular anchoring utilising Fe^III-azotochelin, a natural siderophore, to bind an iridium-containing catalyst to periplasmic siderophore-binding protein (PBP) scaffolds, have previously been synthesised and subjected to catalytic testing. Despite exhibiting high homology and possessing conserved siderophore anchor coordinating residues, the three artificial metalloenzymes (ArMs) displayed significant variability in turnover frequencies (TOFs). To further understand the catalytic properties of these ArMs, their kinetic behaviour was evaluated with respect to the reduction of three cyclic imines: dihydroisoquinoline, harmaline, and papaverine. Kinetic analyses revealed that all examined ArMs adhere to Michaelis-Menten kinetics, with the most pronounced saturation profile observed for the substrate harmaline. Additionally, molecular docking studies suggested varied hydrogen-bonding interactions between substrates and residues within the artificial binding pocket. Pi-stacking and pi-cation interactions were identified for harmaline and papaverine, corroborating the higher affinity of these substrates for the ArMs in comparison to dihydroisoquinoline. Furthermore, it was demonstrated that multiple cavities are capable of accommodating substrates in close proximity to the catalytic centre, thereby rationalising the moderate enantioselectivity conferred by the unmodified scaffolds.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112691"},"PeriodicalIF":3.8,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0162013424002150/pdfft?md5=dd1b980382c9c149dbf91f0c6540dbaa&pid=1-s2.0-S0162013424002150-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141911135","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":"Synthesis and antitumor activity of copper(II) complexes of imidazole derivatives","authors":"Xiaofang Li ,&nbsp;Kaiyong Chen ,&nbsp;Jilei Lai ,&nbsp;Shanshan Wang ,&nbsp;Yihan Chen ,&nbsp;Xiyu Mo ,&nbsp;Zilu Chen","doi":"10.1016/j.jinorgbio.2024.112690","DOIUrl":"10.1016/j.jinorgbio.2024.112690","url":null,"abstract":"<div><p>Complexes [Cu(PI)₂(H₂O)](NO₃)₂ (<strong>1</strong>), [Cu(PBI)₂(NO₃)]NO₃ (<strong>2</strong>), [Cu(TBI)₂(NO₃)]NO₃ (<strong>3</strong>), [Cu(BBIP)₂](ClO₄)₂ (<strong>4</strong>) and [Cu(BBIP)(CH₃OH)(ClO₄)₂] (<strong>5</strong>) were synthesized from the reactions of Cu(II) salts with 2-(2′-pyridyl)imidazole (PI), (2-(2′-pyridyl)benzimidazole (PBI), 2-(4′-thiazolyl)-benzimidazole (TBI), 2,6-bis(benzimidazol-2-yl)-pyridine (BBIP), respectively. Their compositions and crystal structures were determined. Their in-vitro antitumor activities were screened on four cancer cell lines and one normal cell line (HL-7702) using cisplatin as the positive control. Complexes <strong>2</strong> and <strong>4</strong> show higher cytotoxicity than the other three complexes. The cytotoxicity of complex <strong>2</strong> are comparable to those for cisplatin, and the cytotoxicity for <strong>4</strong> are much higher than those for cisplatin. From a viewpoint of antitumor, <strong>2</strong> might be a nice choice on the tumor cell line of T24 because its IC50 values on T24 and HL-7702 are 15.03 ± 1.10 and 21.34 ± 0.35, respectively. Thus, a mechanistic study for complexes <strong>2</strong> and <strong>4</strong> on T24 cells was conducted. It revealed that they can reduce mitochondrial membrane potential and increase mitochondrial membrane permeability, resulting in increased intracellular ROS levels, Ca²⁺ inward flow, dysfunctional mitochondria and the eventual cell apoptosis. In conclusion, they can induce cell apoptosis through mitochondrial dysfunction. These findings could be useful in the development of new antitumor agents.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112690"},"PeriodicalIF":3.8,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141911136","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":"Development of novel organometallic sulfonamides with N-ethyl or N-methyl benzenesulfonamide units as potential human carbonic anhydrase I, II, IX and XII isoforms' inhibitors: Synthesis, biological evaluation and docking studies","authors":"Miguel Gallardo ,&nbsp;Rodrigo Arancibia ,&nbsp;Claudiu T. Supuran ,&nbsp;Alessio Nocentini ,&nbsp;David Villaman ,&nbsp;Patricia M. Toro ,&nbsp;Michelle Muñoz-Osses ,&nbsp;Carolina Mascayano","doi":"10.1016/j.jinorgbio.2024.112689","DOIUrl":"10.1016/j.jinorgbio.2024.112689","url":null,"abstract":"<div><p>In the search of new cymantrenyl- and ferrocenyl-sulfonamides as potencial inhibitors of human carbonic anhydrases (hCAs), four compounds based on <em>N</em>-ethyl or <em>N</em>-methyl benzenesulfonamide units have been obtained. These cymantrenyl (<strong>1a-b</strong>) and ferrocenyl (<strong>2a</strong>-<strong>b</strong>) derivatives were prepared by the reaction between aminobenzene sulfonamides ([NH₂-(CH₂)_n-(C₆H₄)-SO₂-NH₂)], where <em>n</em> = 1, 2) with cymantrenyl sulfonyl chloride (<strong>P1</strong>) or ferrocenyl sulfonyl chloride (<strong>P2</strong>), respectively. All compounds were characterized by conventional spectroscopic techniques and cyclic voltammetry. In the solid state, the molecular structures of compounds <strong>1a</strong>, <strong>1b</strong>, and <strong>2b</strong> were determined by single-crystal X–ray diffraction. Biological evaluation as carbonic anhydrases inhibitors were carried out and showed derivatives <strong>1b</strong> y <strong>2b</strong> present a higher inhibition than the drug control for the Human Carbonic Anhydrase (hCA) II and IX isoforms (K_I = 7.3 nM and 5.8 nM, respectively) and behave as selective inhibition for hCA II isoform. Finally, the docking studies confirmed they share the same binding site and interactions as the known inhibitors acetazolamide (AAZ) and agree with biological studies.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112689"},"PeriodicalIF":3.8,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141911134","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":"Redox-active polyoxovanadates as cofactors in the development of functional protein assemblies","authors":"David E. Salazar Marcano,&nbsp;Jieh-Jang Chen,&nbsp;Mhamad Aly Moussawi,&nbsp;Givi Kalandia,&nbsp;Alexander V. Anyushin,&nbsp;Tatjana N. Parac-Vogt","doi":"10.1016/j.jinorgbio.2024.112687","DOIUrl":"10.1016/j.jinorgbio.2024.112687","url":null,"abstract":"<div><p>The interactions of polyoxovanadates (POVs) with proteins have increasingly attracted interest in recent years due to their potential biomedical applications. This is especially the case because of their redox and catalytic properties, which make them interesting for developing artificial metalloenzymes. Organic-inorganic hybrid hexavanadates in particular offer several advantages over all-inorganic POVs. However, they have been scarcely investigated in biological systems even though, as shown in this work, hybrid hexavanadates are highly stable in aqueous solutions up to relatively high pH. Therefore, a novel bis-biotinylated hexavanadate was synthesized and shown to selectively interact with two biotin-binding proteins, avidin and streptavidin. Bridging interactions between multiple proteins led to their self-assembly into supramolecular bio-inorganic hybrid systems that have potential as artificial enzymes with the hexavanadate core as a redox-active cofactor. Moreover, the structure and charge of the hexavanadate core were determined to enhance the binding affinity and slightly alter the secondary structure of the proteins, which affected the size and speed of formation of the assemblies. Hence, tuning the polyoxometalate (POM) core of hybrid POMs (HPOMs) with protein-binding ligands has been demonstrated to be a potential strategy for controlling the self-assembly process while also enabling the formation of novel POM-based biomaterials that could be of interest in biomedicine.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112687"},"PeriodicalIF":3.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978510","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 pocket hydrogen bonding residue interactions within the Pectobacterium Diguanylate cyclase-containing globin coupled sensor: A resonance Raman study","authors":"Nushrat J. Hoque ,&nbsp;Shannon Rivera ,&nbsp;Paul G. Young ,&nbsp;Emily E. Weinert ,&nbsp;Yilin Liu","doi":"10.1016/j.jinorgbio.2024.112686","DOIUrl":"10.1016/j.jinorgbio.2024.112686","url":null,"abstract":"<div><p>Heme-based sensor proteins are used by organisms to control signaling and physiological effects in response to their gaseous environment. Globin-coupled sensors (GCS) are oxygen-sensing proteins that are widely distributed in bacteria. These proteins consist of a heme globin domain linked by a middle domain to various output domains, including diguanylate cyclase domains, which are responsible for synthesizing <em>c</em>-di-GMP, a bacterial second messenger crucial for regulating biofilm formation. To understand the roles of heme pocket residues in controlling activity of the diguanylate cyclase domain, variants of the <em>Pectobacterium carotovorum</em> GCS (<em>Pcc</em>GCS) were characterized by enzyme kinetics and resonance Raman (rR) spectroscopy. Results of these studies have identified roles for hydrogen bonding and heme edge residues in modulating heme pocket conformation and flexibility. Better understanding of the ligand-dependent GCS signaling mechanism and the residues involved may allow for future development of methods to control O₂-dependent <em>c</em>-di-GMP production.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112686"},"PeriodicalIF":3.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141896402","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":"Repurposing myoglobin into a carbene transferase for a [2,3]-sigmatropic Sommelet-Hauser rearrangement","authors":"Manon Pujol ,&nbsp;Lison Degeilh ,&nbsp;Thibault Sauty de Chalon ,&nbsp;Marius Réglier ,&nbsp;A. Jalila Simaan ,&nbsp;Christophe Decroos","doi":"10.1016/j.jinorgbio.2024.112688","DOIUrl":"10.1016/j.jinorgbio.2024.112688","url":null,"abstract":"<div><p>New-to-Nature biocatalysis has emerged as a promising tool in organic synthesis thanks to progress in protein engineering. Notably, hemeproteins have been evolved into robust catalysts for carbene and nitrene transfers and related sigmatropic rearrangements. In this work, we report the first example of a [2,3]-sigmatropic Sommelet-Hauser rearrangement initiated by a carbene transfer of the sperm whale myoglobin mutant L29S,H64V,V68F that was previously reported to catalyze the mechanistically similar [2,3]-sigmatropic Doyle-Kirmse rearrangement. This repurposed heme enzyme catalyzes the Sommelet-Hauser rearrangement between ethyl diazoacetate and benzyl thioethers bearing strong electron-withdrawing substituents with good yields and enantiomeric excess. Optimized catalytic conditions in the absence of any reductant led to an increased asymmetric induction with up to 59% enantiomeric excess. This myoglobin mutant is therefore one of the few catalysts for the asymmetric Sommelet-Hauser rearrangement. This work broadens the scope of abiological reactions catalyzed by iron-carbene transferases with a new example of asymmetric sigmatropic rearrangement.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112688"},"PeriodicalIF":3.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141900433","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":"The structure of Mn(II)–bound Rubisco from Spinacia oleracea","authors":"Robert W. Voland,&nbsp;Rachael E. Coleman,&nbsp;Kyle M. Lancaster","doi":"10.1016/j.jinorgbio.2024.112682","DOIUrl":"10.1016/j.jinorgbio.2024.112682","url":null,"abstract":"<div><p>The rate of photosynthesis and, thus, CO₂ fixation, is limited by the rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Not only does Rubisco have a relatively low catalytic rate, but it also is promiscuous regarding the metal identity in the active site of the large subunit. In Nature, Rubisco binds either Mg(II) or Mn(II), depending on the chloroplastic ratio of these metal ions; most studies performed with Rubisco have focused on Mg-bound Rubisco. Herein, we report the first crystal structure of a Mn-bound Rubisco, and we compare its structural properties to those of its Mg-bound analogues.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112682"},"PeriodicalIF":3.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141878154","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":"Polyimidazole ligands: Copper(II) complexes and antiproliferative activity in cancer cells","authors":"Fabrizia Brisdelli ,&nbsp;Noemi Bognanni ,&nbsp;Alessandra Piccirilli ,&nbsp;Mariagrazia Perilli ,&nbsp;Denise Bellotti ,&nbsp;Maurizio Remelli ,&nbsp;Graziella Vecchio","doi":"10.1016/j.jinorgbio.2024.112685","DOIUrl":"10.1016/j.jinorgbio.2024.112685","url":null,"abstract":"<div><p>The design of novel chelators for therapeutic applications has been the subject of extensive research to address various diseases. Many chelators can manipulate the levels of metal ions within cells and effectively modulate the metal excess. In some cases, chelators show significant toxicity to cells.</p><p>We investigated polyimidazole ligands by potentiometry and UV–Vis spectroscopy for their ability to form copper(II) complexes. We also compared the antiproliferative activity of the polyimidazole ligands and their copper(II) complexes with polypyridine ligands in CaCo-2 (colorectal adenocarcinoma), SH-SY5Y (neuroblastoma) and K562 (chronic myelogenous leukemia) cells and normal HaCaT (keratinocyte) cells.</p><p>Polyimidazole ligands are less cytotoxic than their analogous polypyridine ligands. All polyimidazole ligands, except the tetraimidazole ligand for K562 cells, did not show any significant effect on the viability of cancer and normal cells. In contrast, the cytotoxic activity of polypiridine ligands was also observed in normal cells with IC₅₀ values similar to those of cancer cells.</p><p>Tetraimidazole ligand, the only ligand active on the leukemic K562 cell line, induced caspase-dependent apoptosis and increased intracellular reactive oxygen species production with mitochondrial damage.</p><p>The low cytotoxicity of the polyimidazole ligands, even if it limits their use as anticancer agents, could make them useful in other medical applications, such as in the treatment of metal overload, microbial infections, inflammation or neurodegenerative disorders.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112685"},"PeriodicalIF":3.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0162013424002095/pdfft?md5=75b64fd9593f4abb499e252ad97fd3cd&pid=1-s2.0-S0162013424002095-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978508","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":"Entrance channels to coproheme in coproporphyrin ferrochelatase probed by exogenous imidazole binding","authors":"Andrea Dali ,&nbsp;Thomas Gabler ,&nbsp;Federico Sebastiani ,&nbsp;Paul G. Furtmüller ,&nbsp;Maurizio Becucci ,&nbsp;Stefan Hofbauer ,&nbsp;Giulietta Smulevich","doi":"10.1016/j.jinorgbio.2024.112681","DOIUrl":"10.1016/j.jinorgbio.2024.112681","url":null,"abstract":"<div><p>Iron insertion into porphyrins is an essential step in heme biosynthesis. In the coproporphyrin-dependent pathway, specific to monoderm bacteria, this reaction is catalyzed by the monomeric enzyme coproporphyrin ferrochelatase. In addition to the mechanistic details of the metalation of the porphyrin, the identification of the substrate access channel for ferrous iron to the active site is important to fully understand this enzymatic system. In fact, whether the iron reaches the active site from the distal or the proximal porphyrin side is still under debate. In this study we have thoroughly addressed this question in <em>Listeria monocytogenes</em> coproporphyrin ferrochelatase by X-ray crystallography, steady-state and pre-steady-state imidazole ligand binding studies, together with a detailed spectroscopic characterization using resonance Raman and UV–vis absorption spectroscopies in solution. Analysis of the X-ray structures of coproporphyrin ferrochelatase-coproporphyrin III crystals soaked with ferrous iron shows that iron is present on both sides of the porphyrin. The kinetic and spectroscopic study of imidazole binding to coproporphyrin ferrochelatase‑iron coproporphyrin III clearly indicates the presence of two possible binding sites in this monomeric enzyme that influence each other, which is confirmed by the observed cooperativity at steady-state and a biphasic behavior in the pre-steady-state experiments. The current results are discussed in the context of the entire heme biosynthetic pathway and pave the way for future studies focusing on protein-protein interactions.</p></div>","PeriodicalId":364,"journal":{"name":"Journal of Inorganic Biochemistry","volume":"260 ","pages":"Article 112681"},"PeriodicalIF":3.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0162013424002058/pdfft?md5=469c947872a1222658468d58e084af00&pid=1-s2.0-S0162013424002058-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141987108","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}