title: Myosin-cross-reactive antigen (MCRA) protein from Bifidobacterium breve is a FAD-dependent fatty acid hydratase which has a function in stress protection.
abstract: BACKGROUND
  The aim of this study was to determine the catalytic activity and physiological role of myosin-cross-reactive antigen (MCRA) from Bifidobacterium breve NCIMB 702258. MCRA from B. breve NCIMB 702258 was cloned, sequenced and expressed in heterologous hosts (Lactococcus and Corynebacterium) and the recombinant proteins assessed for enzymatic activity against fatty acid substrates.
  
  
  RESULTS
  MCRA catalysed the conversion of palmitoleic, oleic and linoleic acids to the corresponding 10-hydroxy fatty acids, but shorter chain fatty acids were not used as substrates, while the presence of trans-double bonds and double bonds beyond the position C12 abolished hydratase activity. The hydroxy fatty acids produced were not metabolised further. We also found that heterologous Lactococcus and Corynebacterium expressing MCRA accumulated increasing amounts of 10-HOA and 10-HOE in the culture medium. Furthermore, the heterologous cultures exhibited less sensitivity to heat and solvent stresses compared to corresponding controls.
  
  
  CONCLUSIONS
  MCRA protein in B. breve can be classified as a FAD-containing double bond hydratase, within the carbon-oxygen lyase family, which may be catalysing the first step in conjugated linoleic acid (CLA) production, and this protein has an additional function in bacterial stress protection.
authors.affiliation: Alimentary Pharmabiotic Centre, Cork, Ireland.
authors.forename: Eva
authors.initials: E
authors.lastname: Rosberg-Cody
authors.forename: Alena
authors.initials: A
authors.lastname: Liavonchanka
authors.forename: Cornelia
authors.initials: C
authors.lastname: Göbel
authors.forename: R Paul
authors.initials: RP
authors.lastname: Ross
authors.forename: Orla
authors.initials: O
authors.lastname: O'Sullivan
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Fitzgerald
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
authors.forename: Catherine
authors.initials: C
authors.lastname: Stanton
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001644:Bifidobacterium / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism*; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D005182:Flavin-Adenine Dinucleotide; D006836:Hydro-Lyases