Genetic and Functional Analysis of the Styrene Catabolic Cluster of Pseudomonas sp. Strain Y2

Abstract

The chromosomal region of Pseudomonas sp. strain Y2 involved in the conversion of styrene to phenylacetate (upper catabolic pathway) has been cloned and sequenced. Four catabolic genes,styABCD, and two regulatory genes, stySR, were identified. This gene cluster when transferred to Escherichia coli W confers to this phenylacetate-degrading host the ability to grow on styrene as the sole carbon and energy source. GenesstyABCD are homologous to those encoding the styrene upper catabolic pathway in Pseudomonas fluorescens ST. Northern blot analyses have confirmed that genes styABCD constitute a transcription unit. The transcription start site of thesty operon was mapped 33 nucleotides upstream of thestyA translational start codon. The styS andstyR genes, which form an independent transcriptional unit, are located upstream of the styABCD operon, and their gene products show high similarity to members of the superfamily of two-component signal transduction systems. The styS gene product is homologous to histidine kinase proteins, whereas thestyR gene product exhibits similarity at its N-terminal domain with cluster 1 of receiver modules and at its C terminus with the LuxR/FixJ family 3 of DNA-binding domains. Expression of the catabolic operon decreased significantly in the absence of thestySR genes and was restored when the stySRgenes were provided in trans in the presence of styrene, suggesting that the stySR system behaves as a styrene-inducible positive regulator of the styABCD operon. Finally, a gene encoding a phenylacetyl-coenzyme A ligase that catalyzes the first step in the phenylacetate catabolism (styrene lower catabolic pathway) has been identified upstream of the stySgene. This activity was found to be induced in Pseudomonassp. strain Y2 cells grown on styrene but not present in cells grown on glycerol. These results strongly suggest that the genes responsible for the complete mineralization of styrene are clustered in the chromosome of Pseudomonas sp. strain Y2.

Recognition of peptidoglycan and β-lactam antibiotics by the extracellular domain of the Ser/Thr protein kinase StkP fromStreptococcus pneumoniae

“…Furthermore, high concentrations of compound 3 did not affect the fluorescence spectrum of an unrelated protein such as the response regulator StyR from Pseudomonas sp. Y2 [28] ( Fig. 7B), which serves as a negative control.…”

Accessing Enantiopure Epoxides and Sulfoxides: Related Flavin‐Dependent Monooxygenases Provide Reversed Enantioselectivity

“…References of GEMs showing activity in the indigo-blue screening are given in blue. Enzymes that were previously mentioned in literature and in several cases biochemically characterized are underlined (ANS32444, ACR43973, ACR43974 [15][16][17] ; BAL04129, BAL04132 [27] ; ASR05591 [50] ; WP_039579272 [51] ; AAC23718 [24] ; CAA73790 [52] ; ABB03727 [53] ; ABX24519 [30] ; CAA04000 [54] ; ADE62390 [55] ; GAC06215, WP_027855270 [56] ; ABV24041 [25] ; ADU39063, ADU39062 [13] ; ENW75087 [11] ; ARO76328 [12] ; WP_081399512 [14] ; APT36898 [57] ; KWR77134 [58] ; ABQ12175 [59] ; ABZ79366 [60] ; GAB22407, CAG69430 [61] ). Amino acid sequences were aligned by using the ClustalW algorithm and after phylogenetic analysis, the maximum likelihood tree was constructed applying the MEGAX software with bootstraps of 1,000 replicates.…”

Metagenomic analysis of a freshwater toxic cyanobacteria bloom

“…The genes of the PhAc catabolon are made of several gene clusters organized into operons and have been identified in a few of the environmentally important aromatic degrading bacteria such as E. coli (designated paa) (Ferrandez et al, 1997), Pseudomonas sp. Y2 (Velasco et al, 1998) and P. putida (designated pha) (Olivera et al, 1998). The arrangement of the operons is somewhat different in the genomes of different species, suggesting that DNA gene and operon rearrangements may have occurred during evolution of the catabolon.…”