A single acyl-CoA dehydrogenase is required for catabolism of isoleucine, valine and short-chain fatty acids in Aspergillus nidulans.
An acyl-CoA dehydrogenase has been identified as part of the mitochondrial beta-oxidation pathway in the ascomycete fungus Aspergillus nidulans. Disruption of the scdA gene prevented use of butyric acid (C(4)) and hexanoic acid (C(6)) as carbon sources and reduced cellular butyryl-CoA dehydrogenase activity by 7.5-fold. While the mutant strain exhibited wild-type levels of growth on erucic acid (C(22:1)) and oleic acid (C(18:1)), some reduction in growth was observed with myristic acid (C(14)). The DeltascdA mutation was found to be epistatic to a mutation downstream in the beta-oxidation pathway (disruption of enoyl-CoA hydratase). The DeltascdA mutant was also unable to use isoleucine or valine as a carbon source. Transcription of scdA was observed in the presence of either fatty acids or amino acids. When the mutant was grown in medium containing either isoleucine or valine, organic acid analysis of culture supernatants showed accumulation of 2-oxo acid intermediates of branched chain amino acid catabolism, suggesting feedback inhibition of the upstream branched-chain alpha-keto acid dehydrogenase.
Maggio-Hall
Lori A
LA
Department of Plant Pathology, University of Wisconsin-Madison, 882 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA.
Lyne
Paul
P
Wolff
Jon A
JA
Keller
Nancy P
NP
D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D044944:Acyl-CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism*; D004883:Erucic Acids / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D005816:Genetic Complementation Test; D007532:Isoleucine / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D009154:Mutation; D019814:Myristic Acid / Q000737:chemistry / Q000378:metabolism; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D014158:Transcription, Genetic; D014633:Valine / Q000378:metabolism*
D000214:Acyl Coenzyme A; D004883:Erucic Acids; D005227:Fatty Acids; D005656:Fungal Proteins; D007532:Isoleucine; C049811:erucic acid; D019814:Myristic Acid; C050106:isobutyryl-coenzyme A; C024343:butyryl-coenzyme A; D019301:Oleic Acid; D044944:Acyl-CoA Dehydrogenases; D014633:Valine