Identification and characterization of the acyclic terpene utilization gene cluster ofPseudomonas citronellolis

Abstract

The catabolism of citronellol and geraniol [acyclic terpene utilization (Atu) pathway] was investigated in Pseudomonas citronellolis. A 13.3-kb genomic DNA fragment was cloned and harboured a putative regulator gene atuR and a gene cluster consisting of eight genes (atuABCDEFGH). Sequence analysis of the atu gene products showed a high degree of amino acid similarity (78-91% identity) to products of a similar gene cluster previously identified in Pseudomonas aeruginosa. Insertion mutagenesis in atuA resulted in inability of the bacteria to utilize acyclic terpenes as a sole source of carbon and energy and confirmed the involvement of atuA in the Atu pathway. Western blot analysis of wild-type and atuA mutant cells of P. citronellolis and P. aeruginosa for biotin-containing proteins enabled the identification of geranyl-CoA carboxylase (GCase), which is the key enzyme of the Atu pathway. GCase subunits were encoded by atuC and atuF. Putative functions for the other Atu proteins in the catabolic pathway of acyclic terpenes are discussed.

The Pseudomonas aeruginosa Isohexenyl Glutaconyl Coenzyme A Hydratase (AtuE) Is Upregulated in Citronellate-Grown Cells and Belongs to the Crotonase Family

“…Those Liu and Atu proteins that were not identified previously (AtuD, LiuE) were clearly identified in the present work and were strongly increased in abundance in citronellate-grown cells. Only AtuH, a predicted acyl-CoA synthetase (a putative citronellyl-CoA synthetase), was not identified in this study or in our previous study (6). The absence of AtuH is in agreement with the absence of a detectable growth defect of atuH insertion mutants on acyclic terpenes (citronellol, citronellate).…”

“…Most of the Atu peptides (AtuA to AtuG) were identified only in citronellate-grown cells and were also significantly increased in abundance (23-to 116-fold). Previous two-dimensional gel electrophoresis data had already shown the specific upregulation of several Liu and Atu proteins in citronellate-grown cells (6). Those Liu and Atu proteins that were not identified previously (AtuD, LiuE) were clearly identified in the present work and were strongly increased in abundance in citronellate-grown cells.…”

“…In particular, the acyclic terpene utilization (Atu) pathway in P. aeruginosa broadens the catabolic capabilities of the species to the utilization of acyclic monoterpenes (1,4). The Atu pathway has been found to involve seven proteins (AtuA, AtuB, AtuCF, AtuD, AtuE, AtuG, AtuH) (5,6). Biochemical studies have not yet verified the function of all Atu proteins.…”

Cloning and Characterization of α-Methylacyl Coenzyme A Racemase from Gordonia polyisoprenivorans VH2

“…Biotinylated carboxylases are key enzymes in degradation of acyclic isoprenoids in some pseudomonads (8,9,11). Therefore, the proteome of G. polyisoprenivorans VH2 was investigated for the presence of biotinylated proteins specially expressed during poly(cis-1,4-isoprene) catabolism (14).…”

Pseudomonas 2007

“…These plantderived aroma compounds have a methyl-branched structure, and to date the only microorganisms known to be capable of utilizing these compounds as carbon and energy sources include Pseudomonas citronellolis, P. aeruginosa, and Pseudomonas mendocina (32). In this study, the genes in the Atu (acyclic terpene utilization) and Liu (leucine/isovalerate utilization) pathways were analyzed in P. aeruginosa.…”