Metabolism of sucrose and its five isomers by Fusobacterium mortiferum.
Fusobacterium mortiferum utilizes sucrose [glucose-fructose in alpha(1-->2) linkage] and its five isomeric alpha-D-glucosyl-D-fructoses as energy sources for growth. Sucrose-grown cells are induced for both sucrose-6-phosphate hydrolase (S6PH) and fructokinase (FK), but the two enzymes are not expressed above constitutive levels during growth on the isomeric compounds. Extracts of cells grown previously on the sucrose isomers trehalulose alpha(1-->1), turanose alpha(1-->3), maltulose alpha(1-->4), leucrose alpha(1-->5) and palatinose alpha(1-->6) contained high levels of an NAD+ plus metal-dependent phospho-alpha-glucosidase (MalH). The latter enzyme was not induced during growth on sucrose. MalH catalysed the hydrolysis of the 6'-phosphorylated derivatives of the five isomers to yield glucose 6-phosphate and fructose, but sucrose 6-phosphate itself was not a substrate. Unexpectedly, MalH hydrolysed both alpha- and beta-linked stereomers of the chromogenic analogue p-nitrophenyl glucoside 6-phosphate. The gene malH is adjacent to malB and malR, which encode an EII(CB) component of the phosphoenolpyruvate-dependent sugar:phosphotransferase system and a putative regulatory protein, respectively. The authors suggest that for F. mortiferum, the products of malB and malH catalyse the phosphorylative translocation and intracellular hydrolysis of the five isomers of sucrose and of related alpha-linked glucosides. Genes homologous to malB and malH are present in both Klebsiella pneumoniae and the enterohaemorrhagic strain Escherichia coli O157:H7. Both these organisms grew well on sucrose, but only K. pneumoniae exhibited growth on the isomeric compounds.
Pikis
Andreas
A
Department of Infectious Diseases, Children's National Medical Center, Washington DC 20010-2970, USA2.|Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1.
Immel
Stefan
S
Institut für Organische Chemie, Technische Universität Darmstadt,D-64287 Darmstadt, Germany3.
Robrish
Stanley A
SA
Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1.
Thompson
John
J
Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1.
D001426:Bacterial Proteins; D019453:Escherichia coli O157 / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005673:Fusobacterium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D007536:Isomerism; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D013395:Sucrose / Q000737:chemistry / Q000378:metabolism*; D000520:alpha-Glucosidases / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D013395:Sucrose; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C107141:phosphoenolpyruvate-maltose phosphotransferase; D010744:Phosphoric Monoester Hydrolases; C022697:sucrose-phosphatase; C049150:maltose-6'-phosphate glucosidase; D000520:alpha-Glucosidases