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Jabeena CA, Rajavelu A. Histone globular domain epigenetic modifications: The regulators of chromatin dynamics in malaria parasite. Chembiochem 2024; 25:e202300596. [PMID: 38078518 DOI: 10.1002/cbic.202300596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/09/2023] [Indexed: 01/31/2024]
Abstract
Plasmodium species adapt a complex lifecycle with multiple phenotypes to survive inside various cell types of humans and mosquitoes. Stage-specific gene expression in the developmental stages of parasites is tightly controlled in Plasmodium species; however, the underlying mechanisms have yet to be explored. Genome organization and gene expression for each stage of the malaria parasite need to be better characterized. Recent studies indicated that epigenetic modifications of histone proteins play a vital role in chromatin plasticity. Like other eukaryotes, Plasmodium species N-terminal tail modifications form a distinct "histone code," which creates the docking sites for histone reader proteins, including gene activator/repressor complexes, to regulate gene expression. The emerging research findings shed light on various unconventional epigenetic changes in histone proteins' core/globular domain regions, which might contribute to the chromatin organization in different developmental stages of the malaria parasite. The malaria parasite lost many transcription factors during evolution, and it is proposed that the nature of local chromatin structure essentially regulates the stage-specific gene expression. This review highlights recent discoveries of unconventional histone globular domain epigenetic modifications and their functions in regulating chromatin structure dynamics in various developmental stages of malaria parasites.
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Affiliation(s)
- C A Jabeena
- Pathogen Biology Group, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P O, Thiruvananthapuram, Kerala, 695014, India
| | - Arumugam Rajavelu
- Pathogen Biology Group, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P O, Thiruvananthapuram, Kerala, 695014, India
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu, 600 036, India
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Que Y, Chan YH, Jia J, Das A, Tong Z, Chang YT, Cui Z, Kumar A, Singh G, Mukherjee S, Lin H, Weber B. A Gate-Tunable Ambipolar Quantum Phase Transition in a Topological Excitonic Insulator. Adv Mater 2024; 36:e2309356. [PMID: 38010877 DOI: 10.1002/adma.202309356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/26/2023] [Indexed: 11/29/2023]
Abstract
Coulomb interactions among electrons and holes in 2D semimetals with overlapping valence and conduction bands can give rise to a correlated insulating ground state via exciton formation and condensation. One candidate material in which such excitonic state uniquely combines with non-trivial band topology are atomic monolayers of tungsten ditelluride (WTe2 ), in which a 2D topological excitonic insulator (2D TEI) forms. However, the detailed mechanism of the 2D bulk gap formation in WTe2 , in particular with regard to the role of Coulomb interactions, has remained a subject of ongoing debate. Here, it shows that WTe2 is susceptible to a gate-tunable quantum phase transition, evident from an abrupt collapse of its 2D bulk energy gap upon ambipolar field-effect doping. Such gate tunability of a 2D TEI, into either n- and p-type semimetals, promises novel handles of control over non-trivial 2D superconductivity with excitonic pairing.
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Affiliation(s)
- Yande Que
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yang-Hao Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
- Physics Division, National Center of Theoretical Physics, Taipei, 10617, Taiwan
| | - Junxiang Jia
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Anirban Das
- Department of Physics, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India
- Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India
| | - Zhengjue Tong
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yu-Tzu Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
| | - Zhenhao Cui
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Amit Kumar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Gagandeep Singh
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Shantanu Mukherjee
- Department of Physics, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India
- Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India
- Quantum Centre for Diamond and Emergent Materials, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, 115201, Taiwan
| | - Bent Weber
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
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Thiruvengetam P, Sunani P, Kumar Chand D. A Metallomicellar Catalyst for Controlled Oxidation of Alcohols and Lignin Mimics in Water using Open Air as Oxidant. ChemSusChem 2024:e202301754. [PMID: 38224525 DOI: 10.1002/cssc.202301754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/06/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
Alcohol groups and β-O-4 (C-C) linkages are widespread in biomass feedstock that are abundant renewable resource for value-added chemicals. The development of sustainable protocols for direct oxidation or oxidative cleavage of feedstock materials in a controlled fashion, using open air as an oxidant is an intellectually stimulating task to produce industrially important value-added carbonyls. Further, the oxidative depolymerization of lignin into fine chemicals has evoked interest in recent times. Herein, we report the first example of a catalyst system that could activate molecular oxygen from atmospheric air for controlled oxidation and oxidative cleavage/depolymerization of feedstock materials such as alcohols, β-O-4 (C-C) linkages and real lignin in water under open air conditions. The selectivity of carbonyl products is controlled by altering the pH between ~7.0 and ~12.0. The current strategy highlights the non-involvement of any external co-catalyst, oxidant, radical additives, and/or destructive organic solvents. The catalyst shows a wide substrate scope and eminent functional group tolerance. The upscaled multigram synthesis using an inexpensive catalyst and easily available oxidant evidences the practical utility of the developed protocol. A plausible mechanism has been proposed with the help of a few controlled experiments, and kinetic and computational studies.
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Affiliation(s)
- Prabaharan Thiruvengetam
- IoE Centre of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Pragyansmruti Sunani
- IoE Centre of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Dillip Kumar Chand
- IoE Centre of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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Kumar S, Patra DK, Rit A. Heterobimetallic Complexes Bridged by an Unsymmetrical Bis(NHC) Ligand: Study of Enhanced Catalytic Activity in Tandem Transformations and Understanding of Cooperativity between the Metal Centers. Chemistry 2023; 29:e202302180. [PMID: 37702918 DOI: 10.1002/chem.202302180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/14/2023]
Abstract
The bis(azolium) salt [L1-H2 ]Br2 was found to serve as a suitable platform for accessing the heterobimetallic IrIII -M (M=PdII /AuI ) and PdII -IrIII complexes. Initially, selective mono-metalation of [L1-H2 ]Br2 yielded an orthometalated IrIII - or non-orthometalated PdII -complex. Sequential metalation of the mono-IrIII complex resulted in the formation of heterobimetallic IrIII -PdII /AuI complexes. Similarly, a distinct heterobimetallic PdII -IrIII complex was synthesized starting from the mono-PdII complex. Further, the corresponding homobimetallic IrIII -IrIII and PdII -PdII complexes were directly obtained from [L1-H2 ]Br2 . Additionally, monometallic PdII and IrIII analogues were synthesized from [L2-H]Br and [L3-H]Br, respectively. The heterobimetallic IrIII -PdII and PdII -IrIII complexes were then evaluated as catalysts in various one-pot tandem catalytic reactions in which they demonstrated superior activity than the mixtures of both their corresponding homobimetallic IrIII -IrIII /PdII -PdII and monometallic IrIII /PdII counterparts, under the constant concentrations of metal centers. Moreover, while comparing complexes IrIII -PdII and PdII -IrIII , the former exhibits higher activity in all the studied reactions. All these findings suggest the presence of some form of cooperativity between the two metal centers (Ir and Pd) connected by a single ligand framework in IrIII -PdII and PdII -IrIII complex, with IrIII -PdII displaying better cooperativity that has been validated by electrochemical, NMR, and DFT studies.
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Affiliation(s)
- Shashi Kumar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Deeptesh K Patra
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Arnab Rit
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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Suthar S, Mondal KC. Open shell versus closed shell bonding interaction in cyclopropane derivatives: EDA-NOCV analyses. J Comput Chem 2023; 44:2184-2211. [PMID: 37530758 DOI: 10.1002/jcc.27190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 08/03/2023]
Abstract
Cyclopropane ring is a very common motif in organic/bio-organic compounds. The chemical bonding of this strained ring is taught to all chemistry students. This three-membered cyclic, C3 ring is quite reactive which has attracted both, synthetic and theoretical chemists to rationalize/correlate its stability and bonding with its reactivity and physical properties over a century. There are a few bonding models (mainly the Bent-Bond model and Walsh model) of this C3 ring that are debated to date. Herein, we have carried out energy decomposition analysis coupled with natural orbital for chemical valence (EDA-NOCV) to study the two most reactive bonds of cyclopropane rings of 49 different organic compounds containing different functional groups to obtain a much deeper bonding insight toward a more general bonding model of this class of compounds. The EDA-NOCV analyses of fragment orbitals and susequent bond formation revealed that the nature of the CC bond of the cyclopropane (splitting two bonds at a time out of three CC bonds) ring is preferred to form two dative covalent CC bonds (between a singlet olefin-fragment and an excited singlet carbene-fragment with a vacant sp2 orbital and a filled p-orbital) for the majority (37/49) of compounds over two covalent electron sharing bonds in some (7/49) compounds (between an excited triplet olefin and triplet carbene), while a few (5/49) compounds show flexibility to adopt either the electron sharing or dative covalent bond as both are equally possible. The effects of functional groups on the nature of chemical bond in cyclopropane rings have been studied in detail. Our bonding analyses are in line with the QTAIM analyses which produce small negative values of the Laplacian, significantly positive values of bond ellipticity, and accumulation of electron densities around the ring critical point of C3 -rings. These corresponding QTAIM parameters of C3 -rings are quite different for CC single bonds of normal hydrocarbons as expected. The chemical bonding in the majority of cyclopropane rings can be very similar to those of metal-olefin systems.
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Affiliation(s)
- Sonam Suthar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India
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Chakraborty P, Nag A, Natarajan G, Bandyopadhyay N, Paramasivam G, Panwar MK, Chakrabarti J, Pradeep T. Rapid isotopic exchange in nanoparticles. Sci Adv 2019; 5:eaau7555. [PMID: 30613775 PMCID: PMC6314871 DOI: 10.1126/sciadv.aau7555] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/27/2018] [Indexed: 05/12/2023]
Abstract
Rapid solution-state exchange dynamics in nanoscale pieces of matter is revealed, taking isotopically pure atomically precise clusters as examples. As two isotopically pure silver clusters made of 107Ag and 109Ag are mixed, an isotopically mixed cluster of the same entity results, similar to the formation of HDO, from H2O and D2O. This spontaneous process is driven by the entropy of mixing and involves events at multiple time scales.
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Affiliation(s)
- Papri Chakraborty
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Abhijit Nag
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Ganapati Natarajan
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Nayanika Bandyopadhyay
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Ganesan Paramasivam
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Manoj Kumar Panwar
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Jaydeb Chakrabarti
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700098, India
| | - Thalappil Pradeep
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
- Corresponding author.
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