Comparative studies in series of cytochrome c oxidase models

Melin, Frédéric; Trivella, Aurélien; Lo, Mamadou; Ruzié, Christian; Hijazi, Ismail; Oueslati, Nesrine; Wytko, Jennifer A.; Boitrel, Bernard; Boudon, Corinne; Hellwig, Petra; Weiss, Jean

doi:10.1016/j.jinorgbio.2011.11.016

Cited by 10 publications

(21 citation statements)

References 23 publications

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“…We have already shown that addition of a strong ‘base’ (e.g., dicyclohexylimidazole) to a heme-peroxo-copper assembly can have a strong influence with respect to subsequent O–O cleavage when protons and/or electrons are added (where a phenol was used as a hydrogen atom source) [19, 20]. The new heme-Fe II -CO species will be employed in the initiation of CO flash photolysis investigations using laser pulses to photoeject CO and observe either CO (as an O 2 -surrogate) or O 2 (flash-and-trap) rebinding [32, 33, 35, 36], to probe how the kinetics and thermodynamics of binding to heme or copper is affected by the ligand environment. Such investigations should provide fundamental information relevant to other synthetic chemical systems (and thus potentially catalytic processes) as well as to biological systems using iron and/or Cu in the utilization of molecular oxygen.…”

Section: Discussionmentioning

confidence: 99%

“…Laser photoejection of CO and the study of the kinetics of CO-rebinding or “flash and trap” experiments to probe the fast reactions between O 2 and heme Fe II complexes also provides a great deal of fundamental information about the active-site nature and/or the O 2 -binding process [25, 30–33]. We have even used heme-carbonyl complexes and photoejection of CO, to study transfer of carbon monoxide to copper(I) complexes whereupon the CO ligand returns to iron [33–36]; this process has relevance to C c O (bio)chemistry [22]. Given this history of chemically or biochemically derived heme-CO complexes, further insights into synthetic aspects and physical properties of heme-CO adducts are still needed, and as mentioned, this information is of value for the study of heme-Cu complex chemistry.…”

Section: Introductionmentioning

confidence: 99%

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New heme–dioxygen and carbon monoxide adducts using pyridyl or imidazolyl tailed porphyrins

Sharma

Karlin

2013

Polyhedron

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Inspired by the chemistry relevant to dioxygen storage, transport and activation by metalloproteins, in particular for heme/copper oxidases, and carbon monoxide binding to metal-containing active sites as a probe or surrogate for dioxygen binding, a series of heme derived dioxygen and CO complexes have been designed, synthesized, and characterized with respect to their physical properties and reactivity. The focus of this study is in the description and comparison of three types heme-superoxo and heme-CO adducts. The starting point is in the characterization of the reduced heme complexes, [(F8)FeII], [(PPy)FeII] and [(PIm)FeII], where F8, PPy and PIm are iron(II)-porphyrinates and where PPy and PIm possess a covalently tethered axial base pyridyl or imidazolyl group, respectively. The spin-state properties of these complexes vary with solvent. The low temperature reaction between O2 and these reduced porphyrin FeII complex yield distinctive low spin heme-superoxo adducts. The dioxygen binding properties for all three complexes are shown to be reversible, via alternate argon or O2 bubbling. Carbon monoxide binds to the reduced heme-FeII precursors to form low spin heme-CO adducts. The implications for future investigations of these heme O2 and CO adducts are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

New heme–dioxygen and carbon monoxide adducts using pyridyl or imidazolyl tailed porphyrins

Sharma

Karlin

2013

Polyhedron

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“…Althought he presence of copperi nt he enzyme provides ar elay for rapid electron transfer,f or phen-strapped porphyrins,i ti s clear that copperb inding also preserves exclusive access to the distal cavity to small exogenic ligands. This selectivity was established for both [7 Fe] + [26] and [9 Fe] + . [28] Whereas the binding of copperi n[ 9 Fe] + is necessary to observe oxygen www.chempluschem.org binding,t he use of sterically hindered picolinic pendant side arms renders [11 Fe] + highlys ensitive to traces of oxygen,i rrespectiveo ft he presence of copperi nt he phen strap.…”

Section: Pendant Coordinating Side Arms:completing the Hemoprotein Momentioning

confidence: 77%

“…Whereas the binding of copper in [ 9 Fe] + is necessary to observe oxygen binding, the use of sterically hindered picolinic pendant side arms renders [ 11 Fe] + highly sensitive to traces of oxygen, irrespective of the presence of copper in the phen strap. Model [ 9 Fe] + also reproduced the behavior of the enzyme in the presence of CO and reversibly formed a photolabile Cu I −CO adduct . These results have shown that a similar binding site containing the same porphyrin unit and a predefined distal side can behave quite differently, despite their significant resemblance.…”

Section: Pendant Coordinating Side Arms: Completing the Hemoprotein Mmentioning

confidence: 97%

“…The efficiency of each modelf or the tetraelectronic reduction of oxygen was assessed by electrochemistry under physiological pH conditions (oxygen-saturated phosphate buffer). [26,27] Analysesf ocusingo nt he nature of the axial bases clearly showst hat the electron-richc haracter of the axial base is of utmost importance and that the presence of copperh as no influence on the reduction potential for iron-bound oxygen. The largesto verpotential versus the uncatalyzed reduction of oxygen is observed for N-alkyl imidazole as an axial base, regardless of the built-in character of the base.…”

Section: Pendant Coordinating Side Arms:completing the Hemoprotein Momentioning

confidence: 99%

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From Models of Hemoproteins to Self‐Assembled Molecular Wires

2017

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In nature, the various properties of tetrapyrrolic macrocycles are mostly due to their proteic environment and result from an evolutionary process that is difficult to reproduce during the lifetime of a synthetic chemist. Thus, the task of synthetic chemists attempting to reproduce the biological role of porphyrin architectures, which perform functions from catalysis to light harvesting, is complicated. This account describes how a phenanthroline‐strapped porphyrin architecture initially designed to afford new hemoprotein models led, over the last two decades, to the preparation of highly linear self‐assembled nano‐objects inspired by light‐harvesting architectures. The approach summarized herein mimics, in a very modest way, the polyvalence of tetrapyrrolic macrocycles found in nature.

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A question of flexibility in cytochrome c oxidase models

Vorburger

Choua

et al. 2017

Inorganica Chimica Acta

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The structure-property relationships were compared for the iron and iron-copper complexes of two functional cytochrome c oxidase models, 1 and 2, both constructed upon a phenanthroline-strapped porphyrin bearing respectively pyridyl or picolinyl built-in proximal and distal ligands. The behavior of these heme models in the absence and in the presence of copper was studied by 1 H NMR, UV-visible absorption, EPR, Raman and FTIR spectroscopies, electrochemistry in solution and deposited on a rotating ring-disk graphite electrode. The distal binding site within the phenanthroline pocket of both 1 and 2 is available for the coordination of exogenic ligands, yet the oxygen binding affinity is higher for all complexes of 2 than for 1.Despite this difference, [1Fe II Cu I ] more efficiently reproduced the electrocatalyzed reduction of 2 oxygen to water than [2Fe II Cu I ]. The oxygenated complexes of both iron(II)-copper(I) species mimic the ability of cytochrome c oxidase to reversibly bind O2, as shown by competitive binding studies in the presence of CO. Differences in the binding and electrocatalytic properties of these models stem from difference in rigidity of scaffolds upon binding of both the proximal and distal ligands, as well as from the bulkiness of the distal ligand. KEYWORDS Cytochrome c oxidase, heme protein models, porphyrin, phenanthroline, oxygen binding, carbon monoxide binding.

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Comparative studies in series of cytochrome c oxidase models

Cited by 10 publications

References 23 publications

New heme–dioxygen and carbon monoxide adducts using pyridyl or imidazolyl tailed porphyrins

New heme–dioxygen and carbon monoxide adducts using pyridyl or imidazolyl tailed porphyrins

From Models of Hemoproteins to Self‐Assembled Molecular Wires

A question of flexibility in cytochrome c oxidase models

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