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Manoj KM, Gideon DA, Parashar A, Nirusimhan V, Annadurai P, Jacob VD, Manekkathodi A. Validating the predictions of murburn model for oxygenic photosynthesis: Analyses of ligand-binding to protein complexes and cross-system comparisons. J Biomol Struct Dyn 2022; 40:11024-11056. [PMID: 34328391 DOI: 10.1080/07391102.2021.1953607] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PS II/Cytochrome b6f complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. We substantiate the proposal that disubstituted phenolics (perceived as protonophores/uncouplers or affinity-based inhibitors in the classical purview) serve as interfacial modulators of diffusible reactive (oxygen) species or DR(O)S. The DRS-based murburn model is evidenced by the identification of multiple ADP-binding sites on the extra-membraneous projection of protein complexes and structure/distribution of the photo/redox catalysts. With a panoramic comparison of the redox metabolic machinery across diverse organellar/cellular systems, we highlight the ubiquitous one-electron murburn facets (cofactors of porphyrin, flavin, FeS, other metal centers and photo/redox active pigments) that enable a facile harnessing of the utility of DRS. In the summative analyses, it is demonstrated that the murburn model of light reaction explains the structures of membrane supercomplexes recently observed in thylakoids and also accounts for several photodynamic experimental observations and evolutionary considerations. In toto, the work provides a new orientation and impetus to photosynthesis research. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kelath Murali Manoj
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Daniel Andrew Gideon
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Abhinav Parashar
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vijay Nirusimhan
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Pushparaj Annadurai
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vivian David Jacob
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Afsal Manekkathodi
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
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Manoj KM, Bazhin NM, Jacob VD, Parashar A, Gideon DA, Manekkathodi A. Structure-function correlations and system dynamics in oxygenic photosynthesis: classical perspectives and murburn precepts. J Biomol Struct Dyn 2022; 40:10997-11023. [PMID: 34323659 DOI: 10.1080/07391102.2021.1953606] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
HIGHLIGHTS Contemporary beliefs on oxygenic photosynthesis are critiqued.Murburn model is suggested as an alternative explanation.In the new model, diffusible reactive species are the main protagonists.All pigments are deemed photo-redox active in the new stochastic mechanism.NADPH synthesis occurs via simple electron transfers, not via elaborate ETC.Oxygenesis is delocalized and not just centered at Mn-Complex.Energetics of murburn proposal for photophosphorylation is provided.The proposal ushers in a paradigm shift in photosynthesis research.
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Affiliation(s)
| | | | - Vivian David Jacob
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | - Abhinav Parashar
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
| | | | - Afsal Manekkathodi
- Satyamjayatu: The Science & Ethics Foundation, Kulappully, Kerala, India
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Murali Manoj K, Bazhin N, Parashar A, Manekkathodi A, Wu Y. Comprehensive Analyses of the Enhancement of Oxygenesis in Photosynthesis by Bicarbonate and Effects of Diverse Additives: Z-scheme Explanation Versus Murburn Model. Physiology (Bethesda) 2022. [DOI: 10.5772/intechopen.106996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The Z-scheme electron transport chain (ETC) explanation for photosynthesis starts with the serial/sequential transfer of electrons sourced from water molecules bound at Photosystem II via a deterministic array of redox centers (of various stationary/mobile proteins), before \"sinking\" via the reduction of NADP+ bound at flavin-enzyme reductase. Several research groups’ finding that additives (like bicarbonate) enhance the light reaction had divided the research community because it violated the Z-scheme. The untenable aspects of the Z-scheme perception were demonstrated earlier and a murburn bioenergetics (a stochastic/parallel paradigm of ion-radical equilibriums) model was proposed to explain photophosphorylation and Emerson effect. Herein, we further support the murburn model with accurate thermodynamic calculations, which show that the cost of one-electron abstraction from bicarbonate [491 kJ/mol] is lower than water [527 kJ/mol]. Further, copious thioredoxin enables the capture of photoactivated electrons in milieu, which aid in the reduction of nicotinamide nucleotides. The diffusible reactive species (DRS) generated in milieu sponsor phosphorylations and oxygenic reactions. With structural analysis of Photosystems and interacting molecules, we chart out the equations of reactions that explain the loss of labeled O-atom traces in delocalized oxygenesis. Thus, this essay discredits the Z-scheme and explains key outstanding observations in the field.
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Manoj KM, Manekkathodi A. Light's interaction with pigments in chloroplasts: The murburn perspective. Journal of Photochemistry and Photobiology 2021. [DOI: 10.1016/j.jpap.2020.100015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Manoj KM, Soman V, David Jacob V, Parashar A, Gideon DA, Kumar M, Manekkathodi A, Ramasamy S, Pakshirajan K, Bazhin NM. Chemiosmotic and murburn explanations for aerobic respiration: Predictive capabilities, structure-function correlations and chemico-physical logic. Arch Biochem Biophys 2019; 676:108128. [PMID: 31622585 DOI: 10.1016/j.abb.2019.108128] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 12/18/2022]
Abstract
Since mid-1970s, the proton-centric proposal of 'chemiosmosis' became the acclaimed explanation for aerobic respiration. Recently, significant theoretical and experimental evidence were presented for an oxygen-centric 'murburn' mechanism of mitochondrial ATP-synthesis. Herein, we compare the predictive capabilities of the two models with respect to the available information on mitochondrial reaction chemistry and the membrane proteins' structure-function correlations. Next, fundamental queries are addressed on thermodynamics of mitochondrial oxidative phosphorylation (mOxPhos): (1) Can the energy of oxygen reduction be utilized for proton transport? (2) Is the trans-membrane proton differential harness-able as a potential energy capable of doing useful work? and (3) Whether the movement of miniscule amounts of mitochondrial protons could give rise to a potential of ~200 mV and if such an electrical energy could sponsor ATP-synthesis. Further, we explore critically if rotary ATPsynthase activity of Complex V can account for physiological ATP-turnovers. We also answer the question- "What is the role of protons in the oxygen-centric murburn scheme of aerobic respiration?" Finally, it is demonstrated that the murburn reaction model explains the fast kinetics, non-integral stoichiometry and high yield of mOxPhos. Strategies are charted to further demarcate the two explanations' relevance in the cellular physiology of aerobic respiration.
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Affiliation(s)
- Kelath Murali Manoj
- Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, 679122, India.
| | - Vidhu Soman
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Vivian David Jacob
- Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, 679122, India
| | - Abhinav Parashar
- Department of Biotechnology, Vignan's Foundation for Science, Technology & Research, Vadlamudi, Guntur, 522213, India
| | - Daniel Andrew Gideon
- Department of Biotechnology & Bioinformatics, Bishop Heber College (Autonomous), Tennur, Tiruchirappalli, 620017, India
| | - Manish Kumar
- Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, 679122, India
| | - Afsal Manekkathodi
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Al-Rayyan PO Box 34110, Qatar
| | - Surjith Ramasamy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Kannan Pakshirajan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Nikolai Mikhailovich Bazhin
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, St. Institutskaya 3, 630090, Novosibirsk, Russia.
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Chang TH, Kunuku S, Kurian J, Manekkathodi A, Chen LJ, Leou KC, Tai NH, Lin IN. Role of carbon nanotube interlayer in enhancing the electron field emission behavior of ultrananocrystalline diamond coated Si-tip arrays. ACS Appl Mater Interfaces 2015; 7:7732-7740. [PMID: 25793425 DOI: 10.1021/acsami.5b00844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We improved the electron field emission properties of ultrananocrystalline diamond (UNCD) films grown on Si-tip arrays by using the carbon nanotubes (CNTs) as interlayer and post-treating the films in CH4/Ar/H2 plasma. The use of CNTs interlayer effectively suppresses the presence of amorphous carbon in the diamond-to-Si interface that enhances the transport of electrons from Si, across the interface, to diamond. The post-treatment process results in hybrid-granular-structured diamond (HiD) films via the induction of the coalescence of the ultrasmall grains in these films that enhanced the conductivity of the films. All these factors contribute toward the enhancement of the electron field emission (EFE) process for the HiDCNT/Si-tip emitters, with low turn-on field of E0 = 2.98 V/μm and a large current density of 1.68 mA/cm(2) at an applied field of 5.0 V/μm. The EFE lifetime stability under an operation current of 6.5 μA was improved substantially to τHiD/CNT/Si-tip = 365 min. Interestingly, these HiDCNT/Si-tip materials also show enhanced plasma illumination behavior, as well as improved robustness against plasma ion bombardment when they are used as the cathode for microplasma devices. The study concludes that the use of CNT interlayers not only increase the potential of these materials as good EFE emitters, but also prove themselves to be good microplasma devices with improved performance.
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Affiliation(s)
- Ting-Hsun Chang
- †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - Srinivasu Kunuku
- §Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - Joji Kurian
- ‡Department of Physics, Tamkang University, Tamsui 251, Taiwan, R.O.C
| | - Afsal Manekkathodi
- †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - Lih-Juann Chen
- †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - Keh-Chyang Leou
- §Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - Nyan-Hwa Tai
- †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C
| | - I-Nan Lin
- ‡Department of Physics, Tamkang University, Tamsui 251, Taiwan, R.O.C
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Wang SC, Lu MY, Manekkathodi A, Liu PH, Lin HC, Li WS, Hou TC, Gwo S, Chen LJ. Complete replacement of metal in metal oxide nanowires via atomic diffusion: In/ZnO case study. Nano Lett 2014; 14:3241-3246. [PMID: 24848685 DOI: 10.1021/nl5006228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Atomic diffusion is a fundamental process that dictates material science and engineering. Direct visualization of atomic diffusion process in ultrahigh vacuum in situ TEM could comprehend the fundamental information about metal-semiconductor interface dynamics, phase transitions, and different nanostructure growth phenomenon. Here, we demonstrate the in situ TEM observations of the complete replacement of ZnO nanowire by indium with different growth directions. In situ TEM analyses reveal that the diffusion processes strongly depend and are dominated by the interface dynamics between indium and ZnO. The diffusion exhibited a distinct ledge migration by surface diffusion at [001]-ZnO while continuous migration with slight/no ledges by inner diffusion at [100]-ZnO. The process is explained based on thermodynamic evaluation and growth kinetics. The results present the potential possibilities to completely replace metal-oxide semiconductors with metal nanowires without oxidation and form crystalline metal nanowires with precise epitaxial metal-semiconductor atomic interface. Formation of such single crystalline metal nanowire without oxidation by diffusion to the metal oxide is unique and is crucial in nanodevice performances, which is rather challenging from a manufacturing perspective of 1D nanodevices.
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Affiliation(s)
- Shau-Chieh Wang
- Department of Materials Science and Engineering and §Department of Physics, National Tsing Hua University , Hsinchu 30013, Taiwan
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Manekkathodi A, Wu YJ, Chu LW, Gwo S, Chou LJ, Chen LJ. Integrated optical waveguide and photodetector arrays based on comb-like ZnO structures. Nanoscale 2013; 5:12185-12191. [PMID: 24132455 DOI: 10.1039/c3nr03735e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
On-chip integrations of photonic waveguides and high-performance electrically-driven devices, by combining different active or passive optical components, are imperative towards the advancement of nanophotonic circuitry systems. We experimentally demonstrate the collective optical functionalities of ZnO microstructures towards designing an integrated photonic system by combining the optical waveguiding and detection properties. Comb-like microstructures composed of periodic arrays of smooth, single-crystalline ZnO nanowires are synthesized for these purposes. We demonstrate that ZnO comb structures could be used as optical waveguides, which can manipulate the blue, green, and red laser beams to an interconnected waveguide array. These results are substantiated by extensive investigation of waveguiding properties of single, stacked or crossbar nanowires, and different branched microstructures. These waveguide arrays can be successfully coupled with another ZnO comb-based photodetector and the collective performances of the integrated optical micro-device units are investigated in detail. This study shows that ZnO comb-based optical waveguide arrays have the great potential to be used as a bottom-up strategy for the construction of various miniaturized photonic demultiplexer systems.
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Affiliation(s)
- Afsal Manekkathodi
- Department of Material Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan ROC.
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Manekkathodi A, Lu MY, Wang CW, Chen LJ. Direct growth of aligned zinc oxide nanorods on paper substrates for low-cost flexible electronics. Adv Mater 2010; 22:4059-63. [PMID: 20512820 DOI: 10.1002/adma.201001289] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Afsal Manekkathodi
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30043, Taiwan
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