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Nayek A, Ahmed ME, Samanta S, Dinda S, Patra S, Dey SG, Dey A. Bioinorganic Chemistry on Electrodes: Methods to Functional Modeling. J Am Chem Soc 2022; 144:8402-8429. [PMID: 35503922 DOI: 10.1021/jacs.2c01842] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
One of the major goals of bioinorganic chemistry has been to mimic the function of elegant metalloenzymes. Such functional modeling has been difficult to attain in solution, in particular, for reactions that require multiple protons and multiple electrons (nH+/ne-). Using a combination of heterogeneous electrochemistry, electrode and molecule design one may control both electron transfer (ET) and proton transfer (PT) of these nH+/ne- reactions. Such control can allow functional modeling of hydrogenases (H+ + e- → 1/2 H2), cytochrome c oxidase (O2 + 4 e- + 4 H+ → 2 H2O), monooxygenases (RR'CH2 + O2 + 2 e- + 2 H+ → RR'CHOH + H2O) and dioxygenases (S + O2 → SO2; S = organic substrate) in aqueous medium and at room temperatures. In addition, these heterogeneous constructs allow probing unnatural bioinspired reactions and estimation of the inner- and outer-sphere reorganization energy of small molecules and proteins.
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Affiliation(s)
- Abhijit Nayek
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Md Estak Ahmed
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Soumya Samanta
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Souvik Dinda
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Suman Patra
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India 700032
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2
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Bhunia S, Ghatak A, Dey A. Second Sphere Effects on Oxygen Reduction and Peroxide Activation by Mononuclear Iron Porphyrins and Related Systems. Chem Rev 2022; 122:12370-12426. [PMID: 35404575 DOI: 10.1021/acs.chemrev.1c01021] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Activation and reduction of O2 and H2O2 by synthetic and biosynthetic iron porphyrin models have proved to be a versatile platform for evaluating second-sphere effects deemed important in naturally occurring heme active sites. Advances in synthetic techniques have made it possible to install different functional groups around the porphyrin ligand, recreating artificial analogues of the proximal and distal sites encountered in the heme proteins. Using judicious choices of these substituents, several of the elegant second-sphere effects that are proposed to be important in the reactivity of key heme proteins have been evaluated under controlled environments, adding fundamental insight into the roles played by these weak interactions in nature. This review presents a detailed description of these efforts and how these have not only demystified these second-sphere effects but also how the knowledge obtained resulted in functional mimics of these heme enzymes.
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Affiliation(s)
- Sarmistha Bhunia
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
| | - Arnab Ghatak
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
| | - Abhishek Dey
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata 700032, India
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3
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Singha A, Mittra K, Dey A. Synthetic heme dioxygen adducts: electronic structure and reactivity. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2021.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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4
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Mondal P, Tolbert GB, Wijeratne GB. Bio-inspired nitrogen oxide (NO x) interconversion reactivities of synthetic heme Compound-I and Compound-II intermediates. J Inorg Biochem 2021; 226:111633. [PMID: 34749065 DOI: 10.1016/j.jinorgbio.2021.111633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
Dioxygen activating heme enzymes have long predicted to be powerhouses for nitrogen oxide interconversion, especially for nitric oxide (NO) oxidation which has far-reaching biological and/or environmental impacts. Lending credence, reactivity of NO with high-valent heme‑oxygen intermediates of globin proteins has recently been implicated in the regulation of a variety of pivotal physiological events such as modulating catalytic activities of various heme enzymes, enhancing antioxidant activity to inhibit oxidative damage, controlling inflammatory and infectious properties within the local heme environments, and NO scavenging. To reveal insights into such crucial biological processes, we have investigated low temperature NO reactivities of two classes of synthetic high-valent heme intermediates, Compound-II and Compound-I. In that, Compound-II rapidly reacts with NO yielding the six-coordinate (NO bound) heme ferric nitrite complex, which upon warming to room temperature converts into the five-coordinate heme ferric nitrite species. These ferric nitrite complexes mediate efficient substrate oxidation reactions liberating NO; i.e., shuttling NO2- back to NO. In contrast, Compound-I and NO proceed through an oxygen-atom transfer process generating the strong nitrating agent NO2, along with the corresponding ferric nitrosyl species that converts to the naked heme ferric parent complex upon warmup. All reaction components have been fully characterized by UV-vis, 2H NMR and EPR spectroscopic methods, mass spectrometry, elemental analyses, and semi-quantitative determination of NO2- anions. The clean, efficient, potentially catalytic NOx interconversions driven by high-valent heme species presented herein illustrate the strong prospects of a heme enzyme/O2/NOx dependent unexplored territory that is central to human physiology, pathology, and therapeutics.
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Affiliation(s)
- Pritam Mondal
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States
| | - Garrett B Tolbert
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States
| | - Gayan B Wijeratne
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States.
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5
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Mondal P, Ishigami I, Gérard EF, Lim C, Yeh SR, de Visser SP, Wijeratne GB. Proton-coupled electron transfer reactivities of electronically divergent heme superoxide intermediates: a kinetic, thermodynamic, and theoretical study. Chem Sci 2021; 12:8872-8883. [PMID: 34257888 PMCID: PMC8246096 DOI: 10.1039/d1sc01952j] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/26/2021] [Indexed: 01/11/2023] Open
Abstract
Heme superoxides are one of the most versatile metallo-intermediates in biology, and they mediate a vast variety of oxidation and oxygenation reactions involving O2(g). Overall proton-coupled electron transfer (PCET) processes they facilitate may proceed via several different mechanistic pathways, attributes of which are not yet fully understood. Herein we present a detailed investigation into concerted PCET events of a series of geometrically similar, but electronically disparate synthetic heme superoxide mimics, where unprecedented, PCET feasibility-determining electronic effects of the heme center have been identified. These electronic factors firmly modulate both thermodynamic and kinetic parameters that are central to PCET, as supported by our experimental and theoretical observations. Consistently, the most electron-deficient superoxide adduct shows the strongest driving force for PCET, whereas the most electron-rich system remains unreactive. The pivotal role of these findings in understanding significant heme systems in biology, as well as in alternative energy applications is also discussed.
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Affiliation(s)
- Pritam Mondal
- Department of Chemistry, University of Alabama at Birmingham Birmingham AL 35205 USA
| | - Izumi Ishigami
- Department of Physiology and Biophysics, Albert Einstein College of Medicine The Bronx New York 10461 USA
| | - Emilie F Gérard
- Manchester Institute of Biotechnology, Department of Chemical Engineering and Analytical Science, The University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Chaeeun Lim
- Department of Chemistry, University of Alabama at Birmingham Birmingham AL 35205 USA
| | - Syun-Ru Yeh
- Department of Physiology and Biophysics, Albert Einstein College of Medicine The Bronx New York 10461 USA
| | - Sam P de Visser
- Manchester Institute of Biotechnology, Department of Chemical Engineering and Analytical Science, The University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Gayan B Wijeratne
- Department of Chemistry, University of Alabama at Birmingham Birmingham AL 35205 USA
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6
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Mukherjee S, Nayek A, Bhunia S, Dey SG, Dey A. A Single Iron Porphyrin Shows pH Dependent Switch between "Push" and "Pull" Effects in Electrochemical Oxygen Reduction. Inorg Chem 2020; 59:14564-14576. [PMID: 32970430 DOI: 10.1021/acs.inorgchem.0c02408] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The "push-pull" effects associated with heme enzymes manifest themselves through highly evolved distal amino acid environments and axial ligands to the heme. These conserved residues enhance their reactivities by orders of magnitude relative to small molecules that mimic the primary coordination. An instance of a mononuclear iron porphyrin with covalently attached pendent phenanthroline groups is reported which exhibit reactivity indicating a pH dependent "push" to "pull" transition in the same molecule. The pendant phenanthroline residues provide proton transfer pathways into the iron site, ensuring selective 4e-/4H+ reduction of O2 to water. The protonation of these residues at lower pH mimics the pull effect of peroxidases, and a coordination of an axial hydroxide ligand at high pH emulates the push effect of P450 monooxygenases. Both effects enhance the rate of O2 reduction by orders of magnitude over its value at neutral pH while maintaining exclusive selectivity for 4e-/4H+ oxygen reduction reaction.
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Affiliation(s)
- Sudipta Mukherjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Abhijit Nayek
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Sarmistha Bhunia
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
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7
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Singha A, Das PK, Dey A. Resonance Raman Spectroscopy and Density Functional Theory Calculations on Ferrous Porphyrin Dioxygen Adducts with Different Axial Ligands: Correlation of Ground State Wave Function and Geometric Parameters with Experimental Vibrational Frequencies. Inorg Chem 2019; 58:10704-10715. [PMID: 31356064 DOI: 10.1021/acs.inorgchem.9b00656] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A dioxygen adduct of ferrous porphyrin is an important chemical species in nature as it is a common intermediate in all oxygen transfer, storage, reducing, and activating heme enzymes. The ground state (GS) wave function of this complex has been investigated using several techniques like resonance Raman (rR), Mossbauer, and X-ray absorption spectroscopies. The Fe-O and O-O vibrations of these six-coordinated diamagnetic species show a positive correlation with each other in contrast to analogous ferrous carbonyl complexes where the Fe-CO vibration correlates negatively with the C-O vibration due to a synergistic effect. In this Article, three Fe-porphyrins with different axial ligands (imidazole, phenolate, and thiolate) are investigated using rR spectroscopy and density functional theory (DFT) calculations. The GS wave functions of these species are analyzed, and the contribution of the three primary bonding interactions in the Fe-O2 unit (a σ interaction from the in-plane π* of the superoxide to the vacant dz2 of Fe, a π donation from the out of plane (oop) π* to the dπ orbital of Fe, and a π back bonding interaction from the dπ orbital of Fe to the oop π* of the superoxide) to the calculated Fe-O and O-O vibrations and bond lengths are deconvoluted using a MO theory framework. The GS wave function provides a basis for the correlations observed between different vibrational and geometric parameters of these dioxygen adducts. Furthermore, the correlations obtained allows estimation of the GS wave function and geometry of these species (both natural and artificial) using their experimentally observed Fe-O/O-O vibrations. The wave functions thus extracted from the experimental vibrational data reported offer insight into the role of the axial ligand and hydrogen bonding on the geometric and electronic structures of these crucial chemical species in different protein active sites.
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Affiliation(s)
- Asmita Singha
- School of Chemical Science , Indian Association for the Cultivation of Science , Kolkata , India 700032
| | - Pradip Kumar Das
- School of Chemical Science , Indian Association for the Cultivation of Science , Kolkata , India 700032
| | - Abhishek Dey
- School of Chemical Science , Indian Association for the Cultivation of Science , Kolkata , India 700032
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8
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Amanullah S, Singha A, Dey A. Tailor made iron porphyrins for investigating axial ligand and distal environment contributions to electronic structure and reactivity. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.01.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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9
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Zhou Y, Shi Y, Wang FB, Xia XH. Oriented Self-Assembled Monolayer of Zn(II)-Tetraphenylporphyrin on TiO2 Electrode for Photoelectrochemical Analysis. Anal Chem 2019; 91:2759-2767. [DOI: 10.1021/acs.analchem.8b04478] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Yue Zhou
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yi Shi
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Feng-Bin Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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10
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Singha A, Dey A. Hydrogen atom abstraction by synthetic heme ferric superoxide and hydroperoxide species. Chem Commun (Camb) 2019; 55:5591-5594. [PMID: 31021337 DOI: 10.1039/c9cc01423c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To date, artificial dioxygen adducts of heme have not been demonstrated to be able to oxidize organic substrates in sharp contrast to their non-heme analogues and naturally occurring enzymes like heme dioxygenases. To address this apparent anomaly, an iron porphyrin complex is synthesized which includes a pendant quinol group. The corresponding dioxygen bound iron porphyrin species is demonstrated to perform hydrogen atom transfer (HAT) from the quinol group appended to the porphyrin ligand. The resultant ferric peroxide, formed by the first HAT, performs a 2nd HAT generating a ferryl species (FeIV[double bond, length as m-dash]O) and resulting in the 2e-/2H+ oxidation of the pendant hydroquinone to quinone.
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Affiliation(s)
- Asmita Singha
- School of Chemical Science, Indian Association for the Cultivation of Science, Kolkata, India.
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11
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Singha A, Mittra K, Dey A. Effect of hydrogen bonding on innocent and non-innocent axial ligands bound to iron porphyrins. Dalton Trans 2019; 48:7179-7186. [DOI: 10.1039/c8dt03852j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Most known heme enzymes utilize hydrogen bonding interactions in their active sites to control electronic and geometric structures and the ensuing reactivity.
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Affiliation(s)
- Asmita Singha
- School of Chemical Science
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Kaustuv Mittra
- School of Chemical Science
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Abhishek Dey
- School of Chemical Science
- Indian Association for the Cultivation of Science
- Kolkata
- India
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12
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Sengupta K, Chatterjee S, Dey A. In Situ Mechanistic Investigation of O2 Reduction by Iron Porphyrin Electrocatalysts Using Surface-Enhanced Resonance Raman Spectroscopy Coupled to Rotating Disk Electrode (SERRS-RDE) Setup. ACS Catal 2016. [DOI: 10.1021/acscatal.6b01122] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Kushal Sengupta
- Department
of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sudipta Chatterjee
- Department
of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Abhishek Dey
- Department
of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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13
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Darnton-Hill I, Mkparu UC. Micronutrients in pregnancy in low- and middle-income countries. Nutrients 2015; 7:1744-68. [PMID: 25763532 PMCID: PMC4377879 DOI: 10.3390/nu7031744] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 02/09/2015] [Accepted: 02/26/2015] [Indexed: 11/21/2022] Open
Abstract
Pregnancy is one of the more important periods in life when increased micronutrients, and macronutrients are most needed by the body; both for the health and well-being of the mother and for the growing foetus and newborn child. This brief review aims to identify the micronutrients (vitamins and minerals) likely to be deficient in women of reproductive age in Low- and Middle-Income Countries (LMIC), especially during pregnancy, and the impact of such deficiencies. A global prevalence of some two billion people at risk of micronutrient deficiencies, and multiple micronutrient deficiencies of many pregnant women in LMIC underline the urgency to establishing the optimal recommendations, including for delivery. It has long been recognized that adequate iron is important for best reproductive outcomes, including gestational cognitive development. Similarly, iodine and calcium have been recognized for their roles in development of the foetus/neonate. Less clear effects of deficiencies of zinc, copper, magnesium and selenium have been reported. Folate sufficiency periconceptionally is recognized both by the practice of providing folic acid in antenatal iron/folic acid supplementation and by increasing numbers of countries fortifying flours with folic acid. Other vitamins likely to be important include vitamins B12, D and A with the water-soluble vitamins generally less likely to be a problem. Epigenetic influences and the likely influence of micronutrient deficiencies on foetal origins of adult chronic diseases are currently being clarified. Micronutrients may have other more subtle, unrecognized effects. The necessity for improved diets and health and sanitation are consistently recommended, although these are not always available to many of the world's pregnant women. Consequently, supplementation programmes, fortification of staples and condiments, and nutrition and health support need to be scaled-up, supported by social and cultural measures. Because of the life-long influences on reproductive outcomes, including inter-generational ones, both clinical and public health measures need to ensure adequate micronutrient intakes during pregnancy, but also during adolescence, the first few years of life, and during lactation. Many antenatal programmes are not currently achieving this. We aim to address the need for micronutrients during pregnancy, the importance of micronutrient deficiencies during gestation and before, and propose the scaling-up of clinical and public health approaches that achieve healthier pregnancies and improved pregnancy outcomes.
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Affiliation(s)
- Ian Darnton-Hill
- The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, University of Sydney, NSW 2006, Australia.
- The Friedman School of Nutrition Science and Policy, Tufts University, Medford, MA 021111, USA.
| | - Uzonna C Mkparu
- Columbia University Medical Center, Institute of Human Nutrition, New York, NY 10027, USA.
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14
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Chatterjee S, Sengupta K, Samanta S, Das PK, Dey A. Electrocatalytic O2 Reduction Reaction by Synthetic Analogues of Cytochrome P450 and Myoglobin: In-Situ Resonance Raman and Dynamic Electrochemistry Investigations. Inorg Chem 2013; 52:9897-907. [DOI: 10.1021/ic401022z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Sudipta Chatterjee
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700032, India
| | - Kushal Sengupta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700032, India
| | - Subhra Samanta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700032, India
| | - Pradip Kumar Das
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700032, India
| | - Abhishek Dey
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700032, India
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15
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Pistner AJ, Lutterman DA, Ghidiu MJ, Ma YZ, Rosenthal J. Synthesis, electrochemistry, and photophysics of a family of phlorin macrocycles that display cooperative fluoride binding. J Am Chem Soc 2013; 135:6601-7. [PMID: 23594346 DOI: 10.1021/ja401391z] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A homologous set of 5,5-dimethylphlorin macrocycles in which the identity of one aryl ring is systematically varied has been prepared. These derivatives contain ancillary pentafluorophenyl (3H(Phl(F))), mesityl (3H(Phl(Mes))), 2,6-bismethoxyphenyl (3H(Phl(OMe))), 4-nitrophenyl (3H(Phl(NO2))), or 4-tert-butylcarboxyphenyl (3H(Phl(CO2tBu))) groups at the 15-meso-position. These porphyrinoids were prepared in good yields (35-50%) and display unusual multielectron redox and photochemical properties. Each phlorin can be oxidized up to three times at modest potentials and can be reduced twice. The electron-donating and electron-releasing properties of the ancillary aryl substituent attenuate the potentials of these redox events; phlorins containing electron-donating aryl groups are easier to oxidize and harder to reduce, while the opposite trend is observed for phlorins containing electron-withdrawing functionalities. Phlorin substitution also has a pronounced effect on the observed photophysics, as introduction of electron-releasing aryl groups on the periphery of the macrocycle is manifest in larger emission quantum yields and longer fluorescence lifetimes. Each phlorin displays an intriguing supramolecular chemistry and can bind 2 equiv of fluoride. This binding is allosteric in nature, and the strength of halide binding correlates with the ability of the phlorin to stabilize the buildup of charge. Moreover, fluoride binding to generate complexes of the form 3H(Phl(R))·2F(-) modulates the redox potentials of the parent phlorin. As such, titration of phlorin with a source of fluoride represents a facile method to tune the ability of this class of porphyrinoid to absorb light and engage in redox chemistry.
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Affiliation(s)
- Allen J Pistner
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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16
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Sengupta K, Chatterjee S, Samanta S, Bandyopadhyay S, Dey A. Resonance Raman and Electrocatalytic Behavior of Thiolate and Imidazole Bound Iron Porphyrin Complexes on Self Assembled Monolayers: Functional Modeling of Cytochrome P450. Inorg Chem 2013; 52:2000-14. [DOI: 10.1021/ic302369v] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kushal Sengupta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Kolkata, India 700032
| | - Sudipta Chatterjee
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Kolkata, India 700032
| | - Subhra Samanta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Kolkata, India 700032
| | - Sabyasachi Bandyopadhyay
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Kolkata, India 700032
| | - Abhishek Dey
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Kolkata, India 700032
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17
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Berto TC, Praneeth VKK, Goodrich LE, Lehnert N. Iron-porphyrin NO complexes with covalently attached N-donor ligands: formation of a stable six-coordinate species in solution. J Am Chem Soc 2010; 131:17116-26. [PMID: 19891503 DOI: 10.1021/ja904368n] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of substituted tetraphenylporphyrin type macrocycles (TMP or To-F(2)PP) with covalently attached N-donor ligands (pyridine or imidazole linker) have been synthesized. Linkers with varying chain lengths and designs have been applied to systematically investigate the effect of chain length and rigidity on the binding affinity of the linker to the corresponding Fe(II)-NO heme complexes. The binding of the linker is monitored in solution using a variety of spectroscopic methods including UV-vis absorption, EPR, and IR spectroscopy. Both the N-O stretching frequency and the imidazole (14)N hyperfine coupling constants show a good correlation with the Fe-(N-donor) bond strength in these systems. The complexes with covalently attached pyridyl and alkyl imidazole ligands only exhibit weak interactions of the linker with iron(II). However, the stable six-coordinate complex [Fe(To-F(2)PP-BzIM)(NO)] (4) is obtained when a rigid benzyl linker is applied. This complex exhibits typical properties of six-coordinate ferrous heme-nitrosyls in which an N-donor ligand is bound trans to NO, including the Soret band at 427 nm and the typical nine line (14)N hyperfine splitting in the EPR spectrum. A crystal structure has been obtained for the corresponding zinc complex. Here, we report the first systematic study on the requirements for the formation of stable six-coordinate ferrous heme nitrosyl complexes in solution at room temperature in the absence of excess axial N-donor ligand.
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Affiliation(s)
- Timothy C Berto
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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18
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Abstract
Iron octamethylporphyrinogens were prepared and structurally characterized in three different oxidation states in the absence of axial ligands and with sodium or tetrafluoroborate as the only counterions. Under these conditions, the iron- and ligand-based redox chemistry of iron porphyrinogens can be defined. The iron center is easily oxidized by a single electron (E(1/2) = -0.57 V vs NHE in CH(3)CN) when confined within the fully reduced macrocycle. The porphyrinogen ligand also undergoes oxidation but in a single four-electron step (E(p) = +0.77 V vs NHE in CH(3)CN); one of the ligand-based electrons is intercepted for the reduction of Fe(III) to Fe(II) to result in an overall three-electron oxidation process. The oxidation equivalents in the macrocycle are stored in C(alpha)-C(alpha) bonds of spirocyclopropane rings, formed between adjacent pyrroles. EPR, magnetic and Mossbauer measurements, and DFT computations of the redox states of the iron porphyrinogens reveal that the reduced ligand gives rise to iron in intermediate spin states, whereas the fully oxidized ligand possesses a weaker sigma-donor framework, giving rise to high-spin iron. Taken together, the results reported herein establish a metal-macrocycle cooperativity that engenders a multielectron chemistry for iron porphyrinogens that is unavailable to heme cofactors.
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Affiliation(s)
- Julien Bachmann
- Department of Chemistry, 6-335, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4207, USA
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19
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Collman JP, Boulatov R, Sunderland CJ, Fu L. Functional Analogues of CytochromecOxidase, Myoglobin, and Hemoglobin. Chem Rev 2004; 104:561-88. [PMID: 14871135 DOI: 10.1021/cr0206059] [Citation(s) in RCA: 516] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James P Collman
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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20
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Bolognesi M, Bordo D, Rizzi M, Tarricone C, Ascenzi P. Nonvertebrate hemoglobins: structural bases for reactivity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1998; 68:29-68. [PMID: 9481144 DOI: 10.1016/s0079-6107(97)00017-5] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- M Bolognesi
- Centro Biotecnologie Avanzate, IST, Università di Genova, Italy
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21
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Abstract
Bovine carbonmonoxy hemoglobin investigated with light scattering studies is found to dissociate from its native tetramer structure into dimers and monomers. The values of the hydrated tetramer radius, RT = 32.1 A, and the fractional dissociation vs pH, have been obtained at different ionic strengths from the autocorrelation function of the scattered light. The results suggest that a relevant contribution to Hb dissociation is due to electrostatic effects and, by means of a model derived by Tanford, it has been possible to predict the behavior of dissociation. Among the findings of this approach, we recall the estimates of the electrostatic energy contributions to Hb dissociation, up to congruent to 6RT, and the predicted charge of tetrameric Hb vs pH, which agrees very well with the experimental data.
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Affiliation(s)
- L Lunelli
- Dipartimento di Fiscia, Università degli Studi, Milano, Italy
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22
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Rizzi M, Ascenzi P, Coda A, Brunori M, Bolognesi M. Molecular bases for heme:ligand recognition in sperm whale (Physeter Catodon) andAplysia limacine myoglobin. ACTA ACUST UNITED AC 1993. [DOI: 10.1007/bf03001186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Abstract
The fundamental relationship between structure and function has served to guide investigations into the workings of living systems at all levels - from the whole organism to individual cells on down to individual molecules. When X-ray crystallography began to reveal the three-dimensional structures of proteins like myoglobin, lysozyme and RNase A, protein chemists were well prepared to draw inferences about functional mechanisms from the precise positioning of amino acid residues they could see. The close proximity between an amino acid side chain and a chemical group on a bound ligand strongly suggests a functional role for that side chain in binding affinity and specificity. Likewise, the nearly universal finding of large clusters of hydrophobic side chains buried in the core of proteins strongly supports a major functional role of hydrophobic interactions in protein folding and stability. Even though eminently plausible hypotheses like these, grounded in the most fundamental principles of chemistry and the logic of structure–function relationships, become widely accepted and make their way into textbooks, protein chemists have felt compelled to search for ways to test them and put them on a more quantitative basis.
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Affiliation(s)
- D Shortle
- Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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