title: Phenotypes of gene disruptants in relation to a putative mitochondrial malate-citrate shuttle protein in citric acid-producing Aspergillus niger.
abstract: The mitochondrial citrate transport protein (CTP) functions as a malate-citrate shuttle catalyzing the exchange of citrate plus a proton for malate between mitochondria and cytosol across the inner mitochondrial membrane in higher eukaryotic organisms. In this study, for functional analysis, we cloned the gene encoding putative CTP (ctpA) of citric acid-producing Aspergillus niger WU-2223L. The gene ctpA encodes a polypeptide consisting 296 amino acids conserved active residues required for citrate transport function. Only in early-log phase, the ctpA disruptant DCTPA-1 showed growth delay, and the amount of citric acid produced by strain DCTPA-1 was smaller than that by parental strain WU-2223L. These results indicate that the CTPA affects growth and thereby citric acid metabolism of A. niger changes, especially in early-log phase, but not citric acid-producing period. This is the first report showing that disruption of ctpA causes changes of phenotypes in relation to citric acid production in A. niger.
authors.affiliation: a Faculty of Science and Engineering, Department of Applied Chemistry , Waseda University , Tokyo , Japan.
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Kirimura
authors.affiliation: a Faculty of Science and Engineering, Department of Applied Chemistry , Waseda University , Tokyo , Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: a Faculty of Science and Engineering, Department of Applied Chemistry , Waseda University , Tokyo , Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Ueda
authors.affiliation: a Faculty of Science and Engineering, Department of Applied Chemistry , Waseda University , Tokyo , Japan.
authors.forename: Takasumi
authors.initials: T
authors.lastname: Hattori
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D002951:Citrates / Q000096:biosynthesis* / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D008293:Malates / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology; D051336:Mitochondrial Membranes / Q000201:enzymology; D010641:Phenotype
chemical_list: D002352:Carrier Proteins; D002951:Citrates; D008293:Malates; C020723:citrate-binding transport protein; D019343:Citric Acid; C030298:malic acid
keywords: Aspergillus niger; citrate transport protein; citric acid production; disruption of ctpA; malate–citrate shuttle