In recent decades, a number of hypotheses on the autotrophic origin of life have been presented. These proposals invoke the emergence of reaction networks leading from CO or CO₂ to the organic molecules required for life. It has also been suggested that the last (universal) common ancestor (LCA or LUCA) of all extant cell lineages was a chemolitho-autotrophic thermophilic anaerobe. The antiquity of some carbon fixation pathways, the phylogenetic basal distribution of some autotrophic organisms, and the catalytic properties of iron-sulfur minerals have been advanced in support of these ideas. Here we critically examine the phylogenetic distribution and evolution of enzymes that are essential for two of the most ancient autotrophic means of metabolism: the reductive tricarboxylic acid (rTCA) cycle and the reductive acetyl-CoA pathway. Phylogenetic analysis of citryl-CoA synthetase and of citryl-CoA lyase, key enzymatic components of the rTCA cycle, and of CO dehydrogenase/acetyl-CoA synthase, a key enzyme in the reductive acetyl-CoA pathway, revealed that all three enzymes have undergone major lateral transfer events and therefore cannot be used as proof of the LCA's metabolic abilities nor as evidence of an autotrophic origin of life.
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http://dx.doi.org/10.2436/20.1501.01.211 | DOI Listing |
FEBS J
December 2024
Institute of Molecular Evolution, Heinrich Heine University Düsseldorf, Germany.
Serpentinizing hydrothermal vents are likely sites for the origin of metabolism because they produce H as a source of electrons for CO reduction while depositing zero-valent iron, cobalt, and nickel as catalysts for organic reactions. Recent work has shown that solid-state nickel can catalyze the H-dependent reduction of CO to various organic acids and their reductive amination with H and NH to biological amino acids under the conditions of H-producing hydrothermal vents and that amino acid synthesis from NH, H, and 2-oxoacids is facile in the presence of Ni. Such reactions suggest a metallic origin of metabolism during early biochemical evolution because single metals replace the function of over 130 enzymatic reactions at the core of metabolism in microbes that use the acetyl-CoA pathway of CO fixation.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
Fatty acid synthesis (FADNS) is a critical process in lipogenesis that is characteristically altered in clear cell renal cell carcinoma (ccRCC), which is the major type of kidney cancer. An important challenge in studying the FADNS process has been the accurate measurement of cytosolic lipogenic acetyl-CoA (AcCoA), the precursor in FADNS, due to its compartmentalization within cells. Here, we describe a novel NMR-based method to decode the isotopic enrichment of lipogenic AcCoA, which, as we demonstrated, is encoded in the simple signal ratios of the geminal methyl groups of lanosterol during its biosynthesis.
View Article and Find Full Text PDFMethods Enzymol
November 2024
Department of Chemistry, Boston University, Cummington Mall, Boston, MA, United States. Electronic address:
The oxo-acid:ferredoxin oxidoreductase (OFOR) superfamily of enzymes are responsible for the reversible interconversion of CO and oxo-acids, using CoA-derivatives as co-substrates, and requiring redox equivalents in the form of a soluble redox-carrier protein ferredoxin (Fd). Ultimately, these enzymes are responsible for the reduction of CO to form pyruvate (in the case of PFOR) and oxo-glutarate (in the case of OGOR), by the reductive carboxylation reaction of acetyl-CoA and succinyl-CoA, respectively. The nature and kind of Fd that is the best redox-carrier to support the reductive reaction has been poorly studied to date.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian 361021, China. Electronic address:
The study aimed to investigate the impacts of a polysaccharide (BFP) from Bangia fusco-purpurea on high-fat diet (HFD)-induced obesity in C57BL/6 mice, as well as its underlying mechanisms. Our results showed that orally administrated BFP was more effective than inulin (INU) in reducing body weight and fat accumulation in obese mice, indicating its anti-obesity effect. BFP effectively improved the compositions and metabolites of intestinal microbiota in obese mice, leading to enhanced energy metabolism and lipid metabolism, thus contributing to its anti-obesity effect.
View Article and Find Full Text PDFJ Agric Food Chem
October 2024
Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Several toxicogenic , such as and , could biosynthesize aflatoxin B (AFB) and other mycotoxins. Chemical fungicides are commonly used to control fungal contamination, but chemical residues may pose significant risks to human health and environmental stability. Consequently, natural antifungal and aflatoxin-inhibiting agents could be sustainable alternatives.
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