The 3,4‐dihydroxyphenylacetic acid catabolon, a catabolic unit for degradation of biogenic amines tyramine and dopamine in Pseudomonas putida U

Abstract

SummaryDegradation of tyramine and dopamine by Pseudomonas putida U involves the participation of twenty one proteins organized in two coupled catabolic pathways, Tyn (tynABFEC tynG tynR tynD, 12 338 bp) and Hpa (hpaR hpaBC hpaHI hpaX hpaG1G2EDF hpaA hpaY, 12 722 bp). The Tyn pathway catalyses the conversion of tyramine and dopamine into 4-hydroxyphenylacetic acid (4HPA) and 3,4-dihydroxyphenylacetic acid (3,4HPA) respectively. Together, the Tyn and Hpa pathways constitute a complex catabolic unit (the 3,4HPA catabolon) in which 3,4HPA is the central intermediate. The genes encoding Tyn proteins are organized in four consecutive transcriptional units (tynABFEC, tynG, tynR and tynD), whereas those encoding Hpa proteins constitute consecutive operons (hpaBC, hpaG1G2EDF, hpaX, hpaHI) and three independent units (hpaA, hpaR and hpaY). Genetic engineering approaches were used to clone tyn and hpa genes and then express them, either individually or in tandem, in plasmids and/or bacterial chromosomes, resulting in recombinant bacterial strains able to eliminate tyramine and dopamine from different media. These results enlarge our biochemical and genetic knowledge of the microbial catabolic routes involved in the degradation of aromatic bioamines. Furthermore, they provide potent biotechnological tools to be used in food processing and fermentation as well as new strategies that could be used for pharmacological and gene therapeutic applications in the near future.

Functional analyses of three acyl‐CoA synthetases involved in bile acid degradation in Pseudomonas putida DOC21

“…Mutants were defined as those strains able to grow on succinate but not on steroids. Genes interrupted by the insertion of the Tn 5 transposon were identified using the strategy described by Arcos and colleagues (). In the text, these mutants are referred to as gene ::Tn 5 .…”

Histamine catabolism in Pseudomonas putida U: identification of the genes, catabolic enzymes and regulators

“…The focus of the present work was the genes and proteins required for Hin catabolism, previously unknown. As demonstrated with other biogenic amines (Arias et al ., ; Arcos et al ., ), P. putida U is able to grow aerobically in MM containing Hin as the sole carbon source (Fig. A).…”

“…). Unlike the genetic organization of the tyramine, dopamine and 2‐phenylethylamine catabolic pathways (Arias et al ., ; Arcos et al ., ), the essential hin genes ( hinABCDGHFLIJK ) were found to be dispersed over the bacterial chromosome, in regions designated hin1 , hin2 and hin3 , and the stand‐alone gene hinK (Fig. ).…”

“…Pseudomonas putida U is able to grow in a chemically defined medium (MM) containing a wide variety of natural or xenobiotic compounds as carbon sources (Martínez-Blanco et al, 1990;Olivera et al, 1998;Arias-Barrau et al, 2004;Arias et al, 2008;Arcos et al, 2010). Over the past three decades, we have taken advantage of the high metabolic flexibility of this bacterium to analyze several catabolic pathways (Martínez-Blanco et al, 1990;Olivera et al, 1998), including those involved in the degradation of biogenic amines (2-phenylethylamine, tyramine and dopamine) (Arias et al, 2008;Arcos et al, 2010). The focus of the present work was the genes and proteins required for Hin catabolism, previously unknown.…”

Plasmids containing the same origin of replication are useful tools to perform biotechnological studies in Pseudomonas putida U and in E. coli DH10B

“…DNA manipulations were performed as indicated elsewhere [8,12,13]. Plasmids were extracted and purified using a GeneJET plasmid MiniprepKit (Thermo Scientific, Lithuania).…”