Publications by authors named "Laurent Jaeken"

7 Publications

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Interaction of membrane-embedded cytochrome b-complexes with quinols: Classical Q-cycle and murburn model.

Cell Biochem Funct 2022 Jan 13. Epub 2022 Jan 13.

Karel de Grote University College, Antwerp University Association, Campus Hoboken, Hoboken, Belgium.

We recently proposed a diffusible reactive (oxygen) species (DRS/DROS) based function for cytochrome b complexes (CBC) and quinones (Q)/quinols (QH ) in the murburn model of bioenergetics. This proposal is in direct conflict with the classical purview of Q-cycle. Via extensive analyses of the structure-function correlations of membrane-quinones/quinols and proteins, we present qualitative and quantitative arguments to infer that the classical model cannot explain the energetics, kinetics, mechanism and probabilistic considerations. Therefore, it is proposed that Q-cycle is neither necessary nor feasible at CBCs. In contrast, we substantiate that the murburn model explains: (a) crucial structural data of CBCs, (b) why quinones/quinols are utilized in bioenergetic membranes, (c) how trans-membrane potential is generated owing to effective charge separation at CBCs, (d) mobility data of O , DRS, Q/QH , and (e) utility of other reaction/membrane components. Further, the murburn model also accommodates the absence of quinones in anaerobic Archaea, wherein methanophenazines are prevalent. The work mandates that the textbooks and research agendas are refreshed to reflect the new perception. SIGNIFICANCE: The current article must be seen as a critical and detailed analysis of the role and working mechanism of quinone (Q) /quinols (QH ) in bioenergetic membranes. In the classical model, QH are perceived as highly mobile electron-transport agents that bind and donate electrons to cytochrome b complexes (CBCs), using sophisticated electronic circuitries, in order to recycle Q and pump protons. The classical perception sees radicals (such as Q*-, O *-, etc., also called diffusible reactive species, DRS) as wasteful or toxic (patho) physiological manifestations. It is highlighted herein that QH has low mobility and matrix has little protons to pump. New insights from the structural analyses of diverse CBCs and quinols, in conjunction with murburn reaction thermodynamics suggest that the electrons from substrates/quinols are effectively utilized via DRS. This perception fits into a much broader analysis of 1 and 2 electron transfers in overall redox metabolism, as recently brought out by the murburn model, wherein DRS are considered obligatory ingredients of physiology. Thus, the findings mandate a reorientation in the pertinent research field.
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http://dx.doi.org/10.1002/cbf.3682DOI Listing
January 2022

Why do cells need oxygen? Insights from mitochondrial composition and function.

Cell Biol Int 2021 Dec 17. Epub 2021 Dec 17.

Industrial Sciences and Technology, Karel de Grote-Hogeschool, Association University and High Schools Antwerp, Antwerpen, Belgium.

Mitochondrial membrane-embedded redox proteins are classically perceived as deterministic "electron transport chain" (ETC) arrays cum proton pumps; and oxygen is seen as an "immobile terminal electron acceptor." This is untenable because: (1) there are little free protons to be pumped out of the matrix; (2) proton pumping would be highly endergonic; (3) ETC-chemiosmosis-rotary ATP synthesis proposal is "irreducibly complex"/"non-evolvable" and does not fit with mitochondrial architecture or structural/distribution data of the concerned proteins/components; (4) a plethora of experimental observations do not conform to the postulates/requisites; for example, there is little evidence for viable proton-pumps/pH-gradient in mitochondria, trans-membrane potential (TMP) is non-fluctuating/non-trappable, oxygen is seen to give copious "diffusible reactive (oxygen) species" (DRS/DROS) in milieu, etc. Quite contrarily, the newly proposed murburn model's tenets agree with known principles of energetics/kinetics, and builds on established structural data and reported observations. In this purview, oxygen is needed to make DRS, the principal component of mitochondrial function. Complex V and porins respectively serve as proton-inlet and turgor-based water-exodus portals, thereby achieving organellar homeostasis. Complexes I to IV possess ADP-binding sites and their redox-centers react/interact with O /DRS. At/around these complexes, DRS cross-react or activate/oxidize ADP/Pi via fast thermogenic one-electron reaction(s), condensing to form two-electron stabilized products (H O /H O/ATP). The varied architecture and distribution of components in mitochondria validate DRS as (i) the coupling agent of oxidative reactions and phosphorylations, and (ii) the primary reason for manifestation of TMP in steady-state. Explorations along the new precepts stand to provide greater insights on mitochondrial function and pathophysiology.
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http://dx.doi.org/10.1002/cbin.11746DOI Listing
December 2021

The neglected functions of intrinsically disordered proteins and the origin of life.

Authors:
Laurent Jaeken

Prog Biophys Mol Biol 2017 07 16;126:31-46. Epub 2017 Mar 16.

Antwerp University Association, Karel de Grote-Hogeschool University College, Department of Industrial Sciences and Technology, Laboratory of Biochemistry, Salesianenlaan 30, B-2660, Hoboken, Belgium. Electronic address:

The example of gelatine shows that extended proteins behave quite differently than globular ones: with water they form a gel. Historically the colloid view of protoplasm was discredited in favour of membrane-(pump)-theory (MPT), but unjustified. In his association-induction hypothesis Ling demonstrates that MPT is full of contradictions and that the colloid view has to be re-considered. In that case IDP's play a crucial role in this. What Ling calls the 'living state' consists of the unitary protoplasmic structure from which it was experimentally demonstrated that it can survive and keep Na and K concentrations without a delineating membrane. It consists of unfolded polypeptide chains whereby the repetitive backbone peptide groups orient and polarise many layers of water, in which Na and other solutes have reduced solubility and whereby the polypeptide β- and ϒ-carboxyl-groups adsorb K. This 'associated' state is the resting state: a coherent high-energy low-entropy meta-stable state. It can be kept by adsorbed ATP (NTP) eventually for years without consumption of ATP as demonstrated by Clegg on Artemia embryo's. Stimuli can transform this state into a lower-energy higher-entropy action state with dissociation of ADP and P and newly synthesised ATP can reinstall it. Rest-to-action and action-to-rest were shown to be real phase-shifts. Ling's theory is a complete quantitative theory with corroborated equations for solute distribution, transport, cell potentials and osmotic behaviour and describing the cell's energy cycle. IDP's are involved in all this. The new view on IDP's leads to new insights on the origin of life.
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http://dx.doi.org/10.1016/j.pbiomolbio.2017.03.002DOI Listing
July 2017

Coherent Behavior and the Bound State of Water and K(+) Imply Another Model of Bioenergetics: Negative Entropy Instead of High-energy Bonds.

Open Biochem J 2012 11;6:139-59. Epub 2012 Dec 11.

Laboratory of Biochemistry, Karel de Grote University College, Department of Applied Engineering, Salesianenlaan 30, B-2660, Antwerp, Belgium.

Observations of coherent cellular behavior cannot be integrated into widely accepted membrane (pump) theory (MT) and its steady state energetics because of the thermal noise of assumed ordinary cell water and freely soluble cytoplasmic K(+). However, Ling disproved MT and proposed an alternative based on coherence, showing that rest (R) and action (A) are two different phases of protoplasm with different energy levels. The R-state is a coherent metastable low-entropy state as water and K(+) are bound to unfolded proteins. The A-state is the higher-entropy state because water and K(+) are free. The R-to-A phase transition is regarded as a mechanism to release energy for biological work, replacing the classical concept of high-energy bonds. Subsequent inactivation during the endergonic A-to-R phase transition needs an input of metabolic energy to restore the low entropy R-state. Matveev's native aggregation hypothesis allows to integrate the energetic details of globular proteins into this view.
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http://dx.doi.org/10.2174/1874091X01206010139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3527877PMC
December 2012

A new list of functions of the cytoskeleton.

Authors:
Laurent Jaeken

IUBMB Life 2007 Mar;59(3):127-33

Industrial Sciences and Technology, Karel de Grote-Hogeschool University College, Hoboken, Belgium.

In classic cell physiology some major properties of life are ignored (coherent behaviour) or not fully integrated (colloid properties), resulting in a limited list of functions of the cytoskeleton. As part of a new paradigm for cell physiology a new list is presented with numerous extra functions, for which experimental evidence has so far accumulated.
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http://dx.doi.org/10.1080/15216540701320593DOI Listing
March 2007

The coherence of life and possible mistakes in classical cell physiology: do we need a paradigm change?

Authors:
Laurent Jaeken

IUBMB Life 2006 Nov;58(11):674-5

Karel de Grote-Hogeschool University College, Department of Industrial Sciences and Technology, Laboratory of Biochemistry, Hoboken, Antwerp, Belgium.

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http://dx.doi.org/10.1080/15216540601002317DOI Listing
November 2006

Linking physiological mechanisms of coherent cellular behaviour with more general physical approaches towards the coherence of life.

Authors:
Laurent Jaeken

IUBMB Life 2006 Nov;58(11):642-6

Karel de Grote-Hogeschool University College, Department of Industrial Sciences and Technology, Laboratory of Biochemistry, Hoboken, Antwerp, Belgium.

Schrödinger pointed out that one of the most fundamental properties of life is its coherent behaviour. This property has been approached from a physiological point of view by Ling in his 'association-induction hypothesis' and extended by Pollack (gel-sol theory), by Chaplin and by Kaivarainen (detailed studies of cellular water). The question of coherence has also been attacked from general physics in three independent approaches: from non-linear thermodynamics (Fröhlich), from quantum field theory (Del Giudice and his group) and from quantum mechanics (Davydov). In this paper all these approaches are unified. The emerging picture constitutes a new paradigm of life.
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http://dx.doi.org/10.1080/15216540601001699DOI Listing
November 2006
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