scholarly journals An artificial cell containing cyanobacteria for endosymbiosis mimicking

2021 ◽  
Author(s):  
Boyu Yang ◽  
Shubin Li ◽  
Wei Mu ◽  
Zhao Wang ◽  
Xiaojun Han
Keyword(s):  
Lactate Dehydrogenase ◽  
Horseradish Peroxidase ◽  
Nicotinamide Adenine Dinucleotide ◽  
Metabolic Pathways ◽  
Glucose Dehydrogenase ◽  
Working Mechanism ◽  
Artificial Cells ◽  
Amplex Red ◽  
Enzyme Cascade ◽  
Artificial Cell

AbstractThe bottom-up constructed artificial cells help to understand the cell working mechanism and provide the evolution clues for organisms. Cyanobacteria are believed to be the ancestors of chloroplasts according to endosymbiosis theory. Herein we demonstrate an artificial cell containing cyanobacteria to mimic endosymbiosis phenomenon. The cyanobacteria sustainably produce glucose molecules by converting light energy into chemical energy. Two downstream “metabolic” pathways starting from glucose molecules are investigated. One involves enzyme cascade reaction to produce H2O2 (assisted by glucose oxidase) first, followed by converting Amplex red to resorufin (assisted by horseradish peroxidase). The more biological one involves nicotinamide adenine dinucleotide (NADH) production in the presence of NAD+ and glucose dehydrogenase. Further, NADH molecules are oxidized into NAD+ by pyruvate catalyzed by lactate dehydrogenase, meanwhile, lactate is obtained. Therefore, the sustainable cascade cycling of NADH/NAD+ is built. The artificial cells built here simulate the endosymbiosis phenomenon, meanwhile pave the way for investigating more complicated sustainable energy supplied metabolism inside artificial cells.

Artificial cells containing sustainable energy conversion engines

2019 ◽  
Vol 3 (5) ◽  
pp. 573-578 ◽  
Author(s):  
Kwanwoo Shin
Keyword(s):  
Energy Conversion ◽  
Nicotinamide Adenine Dinucleotide ◽  
Sustainable Energy ◽  
Living Cells ◽  
Energy Transduction ◽  
Artificial Cells ◽  
Energy Conversion Process ◽  
Metabolic Reactions ◽  
Metabolic Activities ◽  
Reduced Nicotinamide Adenine Dinucleotide

Living cells naturally maintain a variety of metabolic reactions via energy conversion mechanisms that are coupled to proton transfer across cell membranes, thereby producing energy-rich compounds. Until now, researchers have been unable to maintain continuous biochemical reactions in artificially engineered cells, mainly due to the lack of mechanisms that generate energy-rich resources, such as adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). If these metabolic activities in artificial cells are to be sustained, reliable energy transduction strategies must be realized. In this perspective, this article discusses the development of an artificially engineered cell containing a sustainable energy conversion process.

scholarly journals Cholesterol Efflux-Independent Modification of Lipid Rafts by AIBP (Apolipoprotein A-I Binding Protein)

2020 ◽  
Vol 40 (10) ◽  
pp. 2346-2359
Author(s):  
Hann Low ◽  
Nigora Mukhamedova ◽  
Luciano dos Santos Aggum Capettini ◽  
Yining Xia ◽  
Irena Carmichael ◽  
...  
Keyword(s):  
Lipid Rafts ◽  
Nicotinamide Adenine Dinucleotide ◽  
Metabolic Pathways ◽  
Cholesterol Efflux ◽  
Binding Protein ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Underlying Mechanism ◽  
Atp Binding Cassette Transporter ◽  
Apolipoprotein A ◽  
Phosphatidylinositol 3

Objective: AIBP (apolipoprotein A-I binding protein) is an effective and selective regulator of lipid rafts modulating many metabolic pathways originating from the rafts, including inflammation. The mechanism of action was suggested to involve stimulation by AIBP of cholesterol efflux, depleting rafts of cholesterol, which is essential for lipid raft integrity. Here we describe a different mechanism contributing to the regulation of lipid rafts by AIBP. Approach and Results: We demonstrate that modulation of rafts by AIBP may not exclusively depend on the rate of cholesterol efflux or presence of the key regulator of the efflux, ABCA1 (ATP-binding cassette transporter A-I). AIBP interacted with phosphatidylinositol 3-phosphate, which was associated with increased abundance and activation of Cdc42 and rearrangement of the actin cytoskeleton. Cytoskeleton rearrangement was accompanied with reduction of the abundance of lipid rafts, without significant changes in the lipid composition of the rafts. The interaction of AIBP with phosphatidylinositol 3-phosphate was blocked by AIBP substrate, NADPH (nicotinamide adenine dinucleotide phosphate), and both NADPH and silencing of Cdc42 interfered with the ability of AIBP to regulate lipid rafts and cholesterol efflux. Conclusions: Our findings indicate that an underlying mechanism of regulation of lipid rafts by AIBP involves PIP-dependent rearrangement of the cytoskeleton.

scholarly journals A Redox-Neutral, Two-Enzyme Cascade for the Production of Malate and Gluconate from Pyruvate and Glucose

2021 ◽  
Vol 11 (11) ◽  
pp. 4877
Author(s):  
Ravneet Mandair ◽  
Pinar Karagoz ◽  
Roslyn M. Bill
Keyword(s):  
Malate Dehydrogenase ◽  
Closed System ◽  
Glucose Dehydrogenase ◽  
Sulfolobus Solfataricus ◽  
Cofactor Regeneration ◽  
Triple Mutant ◽  
Thermococcus Kodakarensis ◽  
Platform Chemicals ◽  
Enzyme Cascade

A triple mutant of NADP(H)-dependent malate dehydrogenase from thermotolerant Thermococcus kodakarensis has an altered cofactor preference for NAD+, as well as improved malate production compared to wildtype malate dehydrogenase. By combining mutant malate dehydrogenase with glucose dehydrogenase from Sulfolobus solfataricus and NAD+/NADH in a closed reaction environment, gluconate and malate could be produced from pyruvate and glucose. After 3 h, the yield of malate was 15.96 mM. These data demonstrate the feasibility of a closed system capable of cofactor regeneration in the production of platform chemicals.

Kinetics of the oxidation of reduced nicotinamide adenine dinucleotide by horseradish peroxidase compounds I and II

1986 ◽  
Vol 64 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Mohammed A. Kashem ◽  
H. Brian Dunford
Keyword(s):  
Horseradish Peroxidase ◽  
Active Site ◽  
Nicotinamide Adenine Dinucleotide ◽  
Ph Dependence ◽  
Transient State ◽  
Nicotinamide Adenine ◽  
Compound I ◽  
Single Ionization ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Kinetics Of

The transient state kinetics of the oxidation of reduced nicotinamide adenine dinucleotide (NADH) by horseradish peroxidase compound I and II (HRP-I and HRP-II) was investigated as a function of pH at 25.0 °C in aqueous solutions of ionic strength 0.11 using both a stopped-flow apparatus and a conventional spectrophotometer. In agreement with studies using many other substrates, the pH dependence of the HRP-I–NADH reaction can be explained in terms of a single ionization of pKa = 4.7 ± 0.5 at the active site of HRP-I. Contrary to studies with other substrates, the pH dependence of the HRP-H–NADH reaction can be interpreted in terms of a single ionization with pKa of 4.2 ± 1.4 at the active site of HRP-II. An apparent reversibility of the HRP-II–NADH reaction was observed. Over the pH range of 4–10 the rate constant for the reaction of HRP-I with NADH varied from 2.6 × 105 to5.6 × 102 M−1 s−1 and of HRP-II with NADH varied from 4.4 × 104 to 4.1 M−1 s−1. These rate constants must be taken into consideration to explain quantitatively the oxidase reaction of horseradish peroxidase with NADH.

The Identification of the Enzymes That Catalyse the Oxidation of Glyoxylate to Oxalate in the 100 000 g Supernatant Fraction of Human Hyperoxaluric and Control Liver and Heart Tissue

1973 ◽  
Vol 44 (3) ◽  
pp. 227-241 ◽  
Author(s):  
Dorothy A. Gibbs ◽  
R. W. E. Watts
Keyword(s):  
Lactate Dehydrogenase ◽  
Nicotinamide Adenine Dinucleotide ◽  
Liver Tissue ◽  
Primary Hyperoxaluria ◽  
Heart Tissue ◽  
Supernatant Fraction ◽  
Glycollate Oxidase ◽  
And Control ◽  
Oxalate Synthesis ◽  
Lactate Dehydrogenase Isoenzymes

1. The enzymic oxidation of glyoxylate to oxalate in the soluble (100 000 g supernatant) fraction of liver and heart tissue from a patient with primary hyperoxaluria and from a non-hyperoxaluric subject have been studied. 2. An oxidized nicotinamide—adenine dinucleotide (NAD+)-dependent and a non-NAD+-dependent oxidation of glyoxylate to oxalate were observed in the liver tissue from both sources. 3. Evidence is presented that lactate dehydrogenase has a major role in catalysing the reaction in both of the tissues studied. The non-NAD+-dependent oxidations which are catalysed by xanthine oxidase and glycollate oxidase in the liver are relatively unimportant, and they were not detected in the heart. 4. An enzyme that catalyses the oxidation of glycollate was also demonstrated in liver tissue. This had a different electrophoretic mobility from the lactate dehydrogenase isoenzymes. 5. These findings are discussed with particular reference to human primary hyperoxaluria in which excessive oxalate synthesis occurs.

scholarly journals Self-Propulsion Strategies for Artificial Cell-Like Compartments

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1680 ◽  
Author(s):  
Ibon Santiago ◽  
Friedrich C. Simmel
Keyword(s):  
Synthetic Biology ◽  
Biomedical Engineering ◽  
Recent Progress ◽  
Emulsion Droplet ◽  
Artificial Cells ◽  
Droplet Motion ◽  
Active Particles ◽  
Artificial Cell ◽  
Catalytically Active ◽  
A Current

Reconstitution of life-like properties in artificial cells is a current research frontier in synthetic biology. Mimicking metabolism, growth, and sensing are active areas of investigation; however, achieving motility and directional taxis are also challenging in the context of artificial cells. To tackle this problem, recent progress has been made that leverages the tools of active matter physics in synthetic biology. This review surveys the most significant achievements in designing motile cell-like compartments. In this context, strategies for self-propulsion are summarized, including, compartmentalization of catalytically active particles, phoretic propulsion of vesicles and emulsion droplet motion driven by Marangoni flows. This work showcases how the realization of motile protocells may impact biomedical engineering while also aiming at answering fundamental questions in locomotion of prebiotic cells.

The Automated Determination of NAD-Coupled Enzymes

1966 ◽  
Vol 12 (5) ◽  
pp. 274-281 ◽  
Author(s):  
Stanley Morgenstern ◽  
Richard Flor ◽  
Gerald Kessler, ◽  
Bernard Klein
Keyword(s):  
Lactate Dehydrogenase ◽  
Excellent Agreement ◽  
Nicotinamide Adenine Dinucleotide ◽  
Colorimetric Method ◽  
Serum Lactate ◽  
Serum Lactate Dehydrogenase ◽  
Coupled Enzymes ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Automated Determination

Abstract A precise automated procedure developed for determination of serum lactate dehydrogenase, using the Robot Chemist, measures absorbance of a cuprous-neo-cuproine complex formed by coupled reduction of the cupric-neocuproine reagent with enzymatically generated reduced nicotinamide adenine dinucleotide. Activity values obtained by this method, by the identical automated colorimetric method on the AutoAnalyzer, and by an automated spectrophotometric (34O-mµ) procedure show excellent agreement.

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