Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6′‐phosphate phosphatase (MapP) |
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| Authors: | Guillermo D Repizo Céline Henry Andreas Pikis Alexa Bourand María de Fátima Álvarez Stefan Immel Aicha Mechakra‐Maza Axel Hartke John Thompson Christian Magni Josef Deutscher |
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| Institution: | 1. Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, , (S2002LRK) Rosario, Argentina;2. INRA, Microbiologie de l'alimentation au service de la santé humaine (MICALIS), , F‐78350 Jouy en Josas, France;3. AgroParisTech, MICALIS, , F‐78350 Jouy en Josas, France;4. Food and Drug Administration, Center for Drug Evaluation and Research, , Silver Spring, MD, 20993 USA;5. CNRS, MICALIS, , F‐78350 Jouy‐en‐Josas, France;6. Instituto Superior de Investigaciones Biológicas (INSIBIO‐UNT‐CONICET) y Departamento de Biología del Desarrollo, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, , (4000) Tucumán, Argentina;7. Institut für Organische Chemie, Technische Universit?t Darmstadt, , D‐64287 Darmstadt, Germany;8. Laboratory of Environmental Biology, Department of Biochemistry‐Microbiology, Faculty of Natural Science and Life, University Mentouri, , 25017 Constantine, Algeria;9. Université de Caen Basse‐Normandie, , F‐14032 CAEN, France;10. Microbial Biochemistry and Genetics Section, Laboratory of Cell and Developmental Biology, NIDCR, National Institutes of Health, , Bethesda, MD, 20892 USA |
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| Abstract: | Similar to Bacillus subtilis, Enterococcus faecalis transports and phosphorylates maltose via a phosphoenolpyruvate (PEP):maltose phosphotransferase system (PTS). The maltose‐specific PTS permease is encoded by the malT gene. However, E. faecalis lacks a malA gene encoding a 6‐phospho‐α‐glucosidase, which in B. subtilis hydrolyses maltose 6′‐P into glucose and glucose 6‐P. Instead, an operon encoding a maltose phosphorylase (MalP), a phosphoglucomutase and a mutarotase starts upstream from malT. MalP was suggested to split maltose 6‐P into glucose 1‐P and glucose 6‐P. However, purified MalP phosphorolyses maltose but not maltose 6′‐P. We discovered that the gene downstream from malT encodes a novel enzyme (MapP) that dephosphorylates maltose 6′‐P formed by the PTS. The resulting intracellular maltose is cleaved by MalP into glucose and glucose 1‐P. Slow uptake of maltose probably via a maltodextrin ABC transporter allows poor growth for the mapP but not the malP mutant. Synthesis of MapP in a B. subtilis mutant accumulating maltose 6′‐P restored growth on maltose. MapP catalyses the dephosphorylation of intracellular maltose 6′‐P, and the resulting maltose is converted by the B. subtilis maltose phosphorylase into glucose and glucose 1‐P. MapP therefore connects PTS‐mediated maltose uptake to maltose phosphorylase‐catalysed metabolism. Dephosphorylation assays with a wide variety of phospho‐substrates revealed that MapP preferably dephosphorylates disaccharides containing an O‐α‐glycosyl linkage. |
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