title: AspC-mediated aspartate metabolism coordinates the Escherichia coli cell cycle.
abstract: BACKGROUND
  The fast-growing bacterial cell cycle consists of at least two independent cycles of chromosome replication and cell division. To ensure proper cell cycles and viability, chromosome replication and cell division must be coordinated. It has been suggested that metabolism could affect the Escherichia coli cell cycle, but the idea is still lacking solid evidences.
  
  
  RESULTS
  We found that absence of AspC, an aminotransferase that catalyzes synthesis of aspartate, led to generation of small cells with less origins and slow growth. In contrast, excess AspC was found to exert the opposite effect. Further analysis showed that AspC-mediated aspartate metabolism had a specific effect in the cell cycle, as only extra aspartate of the 20 amino acids triggered production of bigger cells with more origins per cell and faster growth. The amount of DnaA protein per cell was found to be changed in response to the availability of AspC. Depletion of (p)ppGpp by ΔrelAΔspoT led to a slight delay in initiation of replication, but did not change the replication pattern found in the ΔaspC mutant.
  The results suggest that AspC-mediated metabolism of aspartate coordinates the E. coli cell cycle through altering the amount of the initiator protein DnaA per cell and the division signal UDP-glucose. Furthermore, AspC sequence conservation suggests similar functions in other organisms.
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.lastname: Qimuge
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Hao
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.
authors.forename: Trond
authors.initials: T
authors.lastname: Bach
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.forename: Lifei
authors.initials: L
authors.lastname: Fan
authors.affiliation: School of Life Sciences, Inner Mongolia University, Hohhot, China.
authors.lastname: Morigen
mesh_terms: D001224:Aspartic Acid / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D002453:Cell Cycle; D017124:Conserved Sequence; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D017353:Gene Deletion; D005798:Genes, Bacterial; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010641:Phenotype; D018741:Replication Origin; D000637:Transaminases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D001224:Aspartic Acid; D006159:Guanosine Tetraphosphate; D000637:Transaminases