Formation of cadaverine derivatives in Saccharomyces cerevisiae

Exploring polyamine metabolism of the yeast-like fungus, Emergomyces africanus

Emergomyces africanus is a thermally dimorphic pathogen causing severe morbidity and mortality in immunocompromized patients. Its transition to a pathogenic yeast-like phase in the human host is a notable virulence mechanism. Recent studies suggest polyamines as key players in dimorphic switching, yet their precise functions remain enigmatic. This work aimed to explore polyamine metabolism of two clinical strains of E. africanus (CBS 136260 and CBS 140360) in mycelial and yeast-like phases. In this first report of the polyamine profile of E. africanus, we reveal, using mass spectrometry, spermidine, and spermine as the major polyamines in both phases. The secretion of these amines was significantly higher in the pathogenic yeast-like phase than in the mycelial phase, warranting further investigation into the implications thereof on virulence. Additionally, we detected the activity of several polyamine biosynthesis enzymes, including arginine decarboxylase, agmatinase, arginase, and ornithine decarboxylase, with significant differences in enzyme expression between morphological phases and strains. Finally, we provide initial evidence for the requirement for spermine, spermidine, and putrescine during the thermally induced dimorphic switch of E. africanus, with strain-specific differences in the production of these amines. Overall, our study presents novel insight into polyamine metabolism and its role in dimorphism of E. africanus.

A link between urease and polyamine metabolism in Cryptococcus neoformans

The urease enzyme of Cryptococcus neoformans is linked to different metabolic pathways within the yeast cell, several of which are involved in polyamine metabolism. Cryptococcal biogenic amine production is, however, largely unexplored and is yet to be investigated in relation to urease. The aim of this study was therefore to explore and compare polyamine metabolism in wild-type, urease-negative and urease-reconstituted strains of C. neoformans. Mass spectrometry analysis showed that agmatine and spermidine were the major extra- and intracellular polyamines of C. neoformans and significant differences were observed between 26 and 37 °C. In addition, compared to the wild-type, the relative percentages of extracellular putrescine and spermidine were found to be lower and agmatine higher in cultures of the urease-deficient mutant. The inverse was true for intracellular spermidine and agmatine. Cyclohexylamine was a more potent polyamine inhibitor compared to DL-α-difluoromethylornithine and inhibitory effects were more pronounced at 37 °C than at 26 °C. At both temperatures, the urease-deficient mutant was less susceptible to cyclohexylamine treatment compared to the wild-type. For both inhibitors, growth inhibition was alleviated with polyamine supplementation. This study has provided novel insight into the polyamine metabolism of C. neoformans, highlighting the involvement of urease in biogenic amine production.

The first agmatine/cadaverine aminopropyl transferase: biochemical and structural characterization of an enzyme involved in polyamine biosynthesis in the hyperthermophilic archaeon Pyrococcus furiosus

We report here the characterization of the first agmatine/cadaverine aminopropyl transferase (ACAPT), the enzyme responsible for polyamine biosynthesis from an archaeon. The gene PF0127 encoding ACAPT in the hyperthermophile Pyrococcus furiosus was cloned and expressed in Escherichia coli, and the recombinant protein was purified to homogeneity. P. furiosus ACAPT is a homodimer of 65 kDa. The broad substrate specificity of the enzyme toward the amine acceptors is unique, as agmatine, 1,3-diaminopropane, putrescine, cadaverine, and sym-nor-spermidine all serve as substrates. While maximal catalytic activity was observed with cadaverine, agmatine was the preferred substrate on the basis of the k(cat)/K(m) value. P. furiosus ACAPT is thermoactive and thermostable with an apparent melting temperature of 108 degrees C that increases to 112 degrees C in the presence of cadaverine. Limited proteolysis indicated that the only proteolytic cleavage site is localized in the C-terminal region and that the C-terminal peptide is not necessary for the integrity of the active site. The crystal structure of the enzyme determined to 1.8-A resolution confirmed its dimeric nature and provided insight into the proteolytic analyses as well as into mechanisms of thermal stability. Analysis of the polyamine content of P. furiosus showed that spermidine, cadaverine, and sym-nor-spermidine are the major components, with small amounts of sym-nor-spermine and N-(3-aminopropyl)cadaverine (APC). This is the first report in Archaea of an unusual polyamine APC that is proposed to play a role in stress adaptation.

Biocatalytic approaches toward the synthesis of both enantiomers of trans-cyclopentane-1,2-diamine

[reaction: see text] A lipase-catalyzed double monoaminolysis of dimethyl malonate by (+/-)-trans-cyclopentane-1,2-diamine allows the sequential resolution of the latter compound, affording an enantiopure bis(amidoester), which is subsequently transformed into an optically active polyamine. As an alternative, both enantiomers of the diamine can be obtained from enantiopure (+)- or (-)-2-aminocyclopentanol, prepared by enzymatic resolution.

Polyamine metabolism in Saccharomyces cerevisiae exposed to ethanol

Growth of the yeast Saccharomyces cerevisiae was unaffected by up to 24 h exposure to ethanol concentrations ranging from 1% to 9%, but was reduced following exposure to 12% ethanol. Concentrations of the polyamines putrescine, cadaverine and spermidine were not affected by a 24 h exposure to 12% ethanol, although there was a significant increase in spermine level. These changes were accompanied by significant increases in the activities of the polyamine biosynthetic enzymes ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) and in the flux of label from ornithine into the polyamines. Formation of the cadaverine derivatives aminopropylcadaverine and N,N-bis(3-aminopropyl)cadaverine was greatly increased in yeast exposed to 12% ethanol for 24 h, probably via the action of ODC, AdoMetDC and the aminopropyltransferases. Exposure to 12% ethanol also led to substantial reductions in the uptake of putrescine and spermidine and the amino acid methionine.

Polyamine metabolism in the thermotolerant mesophilic fungus Aspergillus fumigatus

Biomass production by Aspergillus fumigatus was greatest at 40-45 degrees C and was associated with an increase in concentration of the diamine putrescine and activity of its biosynthetic enzyme ornithine decarboxylase. Concentrations of the other amines, cadaverine, spermidine and spermine were considerably lower than putrescine concentration and did not change significantly over the temperature range 20-50 degrees C. This is surprising in view of the greatly increased flux of label from ornithine through to spermidine at 45 and 50 degrees C, indicating an increased formation of this triamine. It is suggested that there was increased formation of spermidine derivatives at these temperatures. Interestingly, there was greatly increased formation of the higher homologues of cadaverine, aminopropylcadaverine and N,N'-bis(3-aminopropyl)cadaverine, in A. fumigatus at 45 and 50 degrees C.