The ZbYME2 gene from the food spoilage yeast Zygosaccharomyces bailii confers not only YME2 functions in Saccharomyces cerevisiae, but also the capacity for catabolism of sorbate and benzoate, two major weak organic acid preservatives.
A factor influencing resistances of food spoilage microbes to sorbate and benzoate is whether these organisms are able to catalyse the degradation of these preservative compounds. Several fungi metabolize benzoic acid by the beta-ketoadipate pathway, involving the hydroxylation of benzoate to 4-hydroxybenzoate. Saccharomyces cerevisiae is unable to use benzoate as a sole carbon source, apparently through the lack of benzoate-4-hydroxylase activity. However a single gene from the food spoilage yeast Zygosaccharomyces bailii, heterologously expressed in S. cerevisiae cells, can enable growth of the latter on benzoate, sorbate and phenylalanine. Although this ZbYME2 gene is essential for benzoate utilization by Z. bailii, its ZbYme2p product has little homology to other fungal benzoate-4-hydroxylases studied to date, all of which appear to be microsomal cytochrome P450s. Instead, ZbYme2p has strong similarity to the matrix domain of the S. cerevisiae mitochondrial protein Yme2p/Rna12p/Prp12p and, when expressed as a functional fusion to green fluorescent protein in S. cerevisiae growing on benzoate, is largely localized to mitochondria. The phenotypes associated with loss of the native Yme2p from S. cerevisiae, mostly apparent in yme1,yme2 cells, may relate to increased detrimental effects of endogenous oxidative stress. Heterologous expression of ZbYME2 complements these phenotypes, yet it also confers a potential for weak acid preservative catabolism that the native S. cerevisiae Yme2p is unable to provide. Benzoate utilization by S. cerevisiae expressing ZbYME2 requires a functional mitochondrial respiratory chain, but not the native Yme1p and Yme2p of the mitochondrion.
Mollapour
M
M
Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT, UK.
Piper
P W
PW
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000378:metabolism; D019817:Benzoic Acid / Q000378:metabolism*; D005516:Food Microbiology; D005520:Food Preservatives / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D013011:Sorbic Acid / Q000378:metabolism*; D020068:Zygosaccharomyces / Q000235:genetics*
D000935:Antifungal Agents; D005520:Food Preservatives; D005656:Fungal Proteins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D024101:Mitochondrial Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C447835:YME2 protein, Zygosaccharomyces bailii; D049452:Green Fluorescent Proteins; D019817:Benzoic Acid; D049069:ATP-Dependent Proteases; C082702:YME1 protein, S cerevisiae; D000251:Adenosine Triphosphatases; D013011:Sorbic Acid