Publications by authors named "Karin Mardo"

Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a β-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B.

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Article Synopsis
  • Saccharomyces cerevisiae maltases and isomaltases derive from an ancient enzyme (ancMALS) and have evolved to utilize various sugary substrates, suggesting a complex evolutionary path.
  • The study of the maltase protein MAL1 from Ogataea polymorpha reveals that it has a broadened substrate specificity, resembling the characteristics of the ancestral α-glucosidase.
  • Mutations at specific amino acid positions in MAL1 significantly affect its ability to break down maltose-like sugars, and further analysis shows the enzyme has three binding sites, highlighting its substrate interaction capabilities.
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Gut microbiota influences more physiological and developmental processes of humans and animals than earlier expected. Therefore, the possibility to shape the composition and activity of this bacterial population by prebiotics becomes especially important. Inulin, a β-2,1 linked fructan polymer, from plants and fructooligosaccharides (FOS) derived from it are recognized and already widely used as prebiotics while β-2,6 linked fructans have received much less attention from scientific community.

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Article Synopsis
  • Bacterial levansucrases, like Lsc3 from Pseudomonas syringae pv. tomato, effectively convert sucrose into unique β-2,6 linked fructans (FOS) and levan, though the health benefits of these compounds are underexplored.
  • This study evaluates various high-throughput screening methods on 36 Lsc3 mutants to examine their efficiency in sucrose-splitting, FOS production, levan synthesis, and thermostability.
  • Key amino acids Trp109, His113, Glu146, and Glu236 were identified as vital for the catalytic function of Lsc3, and the methodologies developed could potentially be used for studying other enzymes in a cost-effective manner
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The genome of the lactic acid bacterium Lactobacillus plantarum WCFS1 reveals the presence of a rich repertoire of esterases and lipases highlighting their important role in cellular metabolism. Among them is the carboxylesterase LpEst1 a bacterial enzyme related to the mammalian hormone-sensitive lipase, which is known to play a central role in energy homeostasis. In this study, the crystal structure of LpEst1 has been determined at 2.

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Levansucrase encoded by the lsc-3 (lsc3) gene at genomic locus PSPTOA0032 of Pseudomonas syringae pv. tomato DC3000 was mutationally analyzed. Altogether, 18 single-amino-acid mutants of 13 positions of Lsc3 were studied for catalytic properties, including production of fructooligosaccharides (FOS).

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Levansucrases of Pseudomonas syringae pv. tomato DC3000 (Lsc3) and Pseudomonas chlororaphis subsp. aurantiaca (also Pseudomonas aurantiaca) (LscA) have 73% identity of protein sequences, similar substrate specificity and kinetic properties.

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