Characterization of FerC, a MarR-type transcriptional regulator, involved in transcriptional regulation of the ferulate catabolic operon in Sphingobium sp. strain SYK-6

Abstract

Sphingobium sp. strain SYK-6 is able to degrade various lignin-derived aromatic compounds including ferulate, vanillate, and syringate. In the SYK-6 cells, ferulate is converted to vanillin and acetyl-coenzyme A (acetyl-CoA) through the reactions catalyzed by feruloyl-CoA synthetase and feruloyl-CoA hydratase/lyase encoded by ferA and ferB, respectively. Here, we characterized the transcriptional regulation of ferBA controlled by a MarR-type transcriptional regulator, FerC. The ferC gene is located upstream of ferB. Reverse transcription (RT)-PCR analysis suggested that the ferBA genes form an operon. Quantitative RT-PCR analyses of SYK-6 and its mutant cells revealed that the transcription of the ferBA operon is negatively regulated by FerC, and feruloyl-CoA was identified as an inducer. The transcription start site of ferB was mapped at 30 nucleotides upstream from the ferB initiation codon. Purified His-tagged FerC bound to the ferC-ferB intergenic region. This region contains an inverted repeat sequence, which overlaps with a part of the -10 sequence and the transcriptional start site of ferB. The binding of FerC to the operator sequence was inhibited by the addition of feruloyl-CoA, indicating that FerC interacts with feruloyl-CoA as an effector molecule. Furthermore, hydroxycinnamoyl-CoAs, including p-coumaroyl-CoA, caffeoyl-CoA, and sinapoyl-CoA also acted as effector.

A bacterial aromatic aldehyde dehydrogenase critical for the efficient catabolism of syringaldehyde

“…Sphingobium sp. SYK-6 and its mutant derivatives were routinely grown at 30 °C in Lysogeny broth (LB) or Wx minimal salt medium44 containing 5 mM SN, 5 mM VN, or SEMP (10 mM sucrose, 10 mM glutamate, 0.13 mM methionine, and 10 mM proline). When necessary, 50 mg of kanamycin (Km)/liter, 30 mg of chloramphenicol (Cm)/liter, and 12.5 mg of tetracycline (Tc)/liter were added to the cultures.…”

Membrane-Associated Glucose-Methanol-Choline Oxidoreductase Family Enzymes PhcC and PhcD Are Essential for Enantioselective Catabolism of Dehydrodiconiferyl Alcohol

“…Sphingobium sp. strain SYK-6 and its mutants were grown in lysogeny broth (LB; 10 g/liter of Bacto tryptone, 5 g/liter of yeast extract, and 5 g/liter of NaCl) and Wx minimal medium (25) containing SEMP (10 mM sucrose, 10 mM glutamate, 0.13 mM methionine, and 10 mM proline) and 2 mM DCA or DCA-C at 30°C. When necessary, 50 mg of kanamycin (Km)/liter was added to the cultures.…”

“…strain SYK-6, is the best-characterized bacterial degrader of lignin-derived aromatic compounds (19). The catabolic pathways and catabolic genes in this strain for ␤-aryl ether (13)(14)(15), biphenyl (20)(21)(22), pinoresinol (23), ferulate (24,25), vanillin (26,27), and syringate (28) have been extensively characterized. However, the catabolic genes for a phenylcoumaran compound, dehydrodiconiferyl alco-hol (DCA), remain largely unknown.…”

Rhizobacter gummiphilus sp. nov., a rubber-degrading bacterium isolated from the soil of a botanical garden in Japan

“…The strain NS21 was grown at 30 C on a Wx minimal salt agar medium (Kasai et al, 2012) containing 0.4% deproteinized natural rubber (DPNR, Chaikumpollert et al, 2012). Rhizobacter dauci H6 T , Rhizobacter fulvus Gsoil 322 T , Rivibacter subsaxonicus BF49 T and Piscinibacter aquaticus NBRC 102349 T were grown in R2A medium (Difco), and their gyrB sequences were analyzed.…”