Novel metabolic pathway for N-methylpyrrolidone degradation in Alicycliphilus sp. strain BQ1
Por:
Julieta Solis-Gonzalez, Claudia, Dominguez-Malfavon, Lilianha, Vargas-Suarez, Martin, Gaytan, Itzel, Angel Cevallos, Miguel, Lozano, Luis, Javier Cruz-Gomez, M., Loza-Tavera, Herminia
Publicada:
1 ene 2018
Resumen:
The molecular mechanisms underlying the biodegradation of N-methylpyrrolidone (NMP), a widely used industrial solvent that produces skin irritation in humans and is teratogenic in rats, are unknown. Alicycliphilus sp. strain BQ1 degrades NMP. By studying a transposon-tagged mutant unable to degrade NMP, we identified a six-gene cluster (nmpABCDEF) that is transcribed as a polycistronic mRNA and encodes enzymes involved in NMP biodegradation. nmpA and the transposonaffected gene nmpB encode an N-methylhydantoin amidohydrolase that transforms NMP to ?-N-methylaminobutyric acid; this is metabolized by an amino acid oxidase (NMPC), either by demethylation to produce ?-aminobutyric acid (GABA) or by deamination to produce succinate semialdehyde (SSA). If GABA is produced, the activity of a GABA aminotransferase (GABA-AT), not encoded in the nmp gene cluster, is needed to generate SSA. SSA is transformed by a succinate semialdehyde dehydrogenase (SSDH) (NMPF) to succinate, which enters the Krebs cycle. The abilities to consume NMP and to utilize it for growth were complemented in the transposontagged mutant by use of the nmpABCD genes. Similarly, Escherichia coli MG1655, which has two SSDHs but is unable to grow in NMP, acquired these abilities after functional complementation with these genes. In wild-type (wt) BQ1 cells growing in NMP, GABA was not detected, but SSA was present at double the amount found in cells growing in Luria-Bertani medium (LB), suggesting that GABA is not an intermediate in this pathway. Moreover, E. coli GABA-AT deletion mutants complemented with nmpABCD genes retained the ability to grow in NMP, supporting the possibility that ?-N-methylaminobutyric acid is deaminated to SSA instead of being demethylated to GABA. © 2017 American Society for Microbiology.
Filiaciones:
Julieta Solis-Gonzalez, Claudia:
Univ Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City, DF, Mexico
Dominguez-Malfavon, Lilianha:
Univ Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City, DF, Mexico
Vargas-Suarez, Martin:
Univ Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City, DF, Mexico
Gaytan, Itzel:
Univ Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City, DF, Mexico
Angel Cevallos, Miguel:
Univ Nacl Autonoma Mexico, Ctr Ciencias Genom, Programa Genom Evolutiva, Cuernavaca, Morelos, Mexico
Lozano, Luis:
Univ Nacl Autonoma Mexico, Ctr Ciencias Genom, Programa Genom Evolutiva, Cuernavaca, Morelos, Mexico
Javier Cruz-Gomez, M.:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Ingn Quim, Mexico City, DF, Mexico
Loza-Tavera, Herminia:
Univ Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City, DF, Mexico
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