title: Genetic and physiological characterization of the Borrelia burgdorferi ORF BB0374-pfs-metK-luxS operon.
abstract: The Lyme disease spirochaete, Borrelia burgdorferi, produces the LuxS enzyme both in vivo and in vitro; this enzyme catalyses the synthesis of homocysteine and 4,5-dihydroxy-2,3-pentanedione (DPD) from a by-product of methylation reactions. Unlike most bacteria, B. burgdorferi is unable to utilize homocysteine. However, DPD levels alter expression levels of a subset of B. burgdorferi proteins. The present studies demonstrate that a single B. burgdorferi operon encodes both of the enzymes responsible for synthesis of DPD, as well as the enzyme for production of the Lyme spirochaete's only activated-methyl donor and a probable phosphohydrolase. Evidence was found for only a single transcriptional promoter, located 5' of the first gene, which uses the housekeeping sigma(70) subunit for RNA polymerase holoenzyme function. All four genes are co-expressed, and mRNA levels are growth-rate dependent, being produced during the exponential phase. Thus, high metabolic activity is accompanied by increased cellular levels of the only known borrelial methyl donor, enhanced detoxification of methylation by-products, and increased production of DPD. Therefore, production of DPD is directly correlated with cellular metabolism levels, and may thereby function as an extracellular and/or intracellular signal of bacterial health.
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, MS415 Chandler Medical Center, Lexington, KY 40536-0298, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Riley
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, MS415 Chandler Medical Center, Lexington, KY 40536-0298, USA.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Bykowski
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, MS415 Chandler Medical Center, Lexington, KY 40536-0298, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Babb
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, MS415 Chandler Medical Center, Lexington, KY 40536-0298, USA.
authors.forename: Kate
authors.initials: K
authors.lastname: von Lackum
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, MS415 Chandler Medical Center, Lexington, KY 40536-0298, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Stevenson
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D025065:Borrelia burgdorferi / Q000235:genetics* / Q000472:pathogenicity; D013437:Carbon-Sulfur Lyases / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism*; D008716:Methionine Adenosyltransferase / Q000378:metabolism; D016366:Open Reading Frames; D009876:Operon / Q000235:genetics; D010420:Pentanes / Q000378:metabolism*
chemical_list: C493138:4,5-dihydroxy-2,3-pentanedione; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010420:Pentanes; D006714:Homoserine; C519385:MetK protein, E coli; D008716:Methionine Adenosyltransferase; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria