title: De novo synthesis of fatty acids is regulated by FapR protein in Exiguobacterium antarcticum B7, a psychrotrophic bacterium isolated from Antarctica.
abstract: BACKGROUND
  FapR protein from the psychrotrophic species Exiguobacterium antarcticum B7 was expressed and purified, and subsequently evaluated for its capacity to bind to the promoter regions of the fabH1-fabF and fapR-plsX-fabD-fabG operons, using electrophoretic mobility shift assay. The genes that compose these operons encode for enzymes involved in the de novo synthesis of fatty acids molecules. In Bacillus subtilis, FapR regulates the expression of these operons, and consequently has influence in the synthesis of long or short-chain fatty acids. To analyze the bacterial cold adaptation, this is an important metabolic pathway because psychrotrophic microrganisms tend to synthesize short and branched-chain unsaturated fatty acids at cold to maintain cell membrane fluidity.
  
  
  RESULTS
  In this work, it was observed that recombinant protein was able to bind to the promoter of the fully amplified fabH1-fabF and fapR-plsX-fabD-fabG operons. However, FapR was unable to bind to the promoter of fapR-plsX-fabD-fabG operon when synthesized only up to the protein-binding palindrome 5'-TTAGTACCAGATACTAA-3', thus showing the importance of the entire promoter sequence for the correct protein-DNA interaction.
  
  
  CONCLUSIONS
  Through this observation, we demonstrate that the FapR protein possibly regulates the same operons as described for other species, which emphasizes its importance to cold adaptation process of E. antarcticum B7, a psychrotrophic bacterium isolated at Antarctica.
authors.affiliation: Laboratório de Genômica e Bioinformática, Centro de Genômica e Biologia de Sistemas, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, 66075-110, Brazil. rabarauna@ufpa.br.
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Baraúna
authors.affiliation: Laboratório de Genômica e Bioinformática, Centro de Genômica e Biologia de Sistemas, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, 66075-110, Brazil.
authors.forename: Diego A
authors.initials: DA
authors.lastname: das Graças
authors.affiliation: REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Campus de Caparica, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
authors.forename: Catarina I P
authors.initials: CI
authors.lastname: Nunes
authors.affiliation: Laboratório de Genômica e Bioinformática, Centro de Genômica e Biologia de Sistemas, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, 66075-110, Brazil.
authors.forename: Maria P C
authors.initials: MP
authors.lastname: Schneider
authors.affiliation: Laboratório de Genômica e Bioinformática, Centro de Genômica e Biologia de Sistemas, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, 66075-110, Brazil.
authors.forename: Artur
authors.initials: A
authors.lastname: Silva
authors.affiliation: REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Campus de Caparica, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal. marta.carepo@fct.unl.pt.
authors.forename: Marta S P
authors.initials: MS
authors.lastname: Carepo
mesh_terms: D000864:Antarctic Regions; D001407:Bacillus / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D005227:Fatty Acids / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids
keywords: Antarctica; Exiguobacterium antarcticum; FapR; Psychrotrophic