Genetic analysis of coenzyme A biosynthesis in the yeast Saccharomyces cerevisiae: identification of a conditional mutation in the pantothenate kinase gene CAB1.
Coenzyme A (CoA) is a ubiquitous cofactor required for numerous enzymatic carbon group transfer reactions. CoA biosynthesis requires contributions from various amino acids with pantothenate as an important intermediate which can be imported from the medium or synthesized de novo. Investigating function and expression of structural genes involved in CoA biosynthesis of the yeast Saccharomyces cerevisiae, we show that deletion of ECM31 and PAN6 results in mutants requiring pantothenate while loss of PAN5 (related to panE from E. coli) still allows prototrophic growth. A temperature-sensitive mutant defective for fatty acid synthase activity could be functionally complemented by a gene significantly similar to eukaryotic pantothenate kinases (YDR531W). Enzymatic studies and heterologous complementation of this mutation by bacterial and mammalian genes showed that YDR531W encodes a genuine pantothenate kinase (new gene designation: CAB1, "coenzyme A biosynthesis"). A G351S missense mutation within CAB1 was identified to cause the conditional phenotype of the mutant initially studied. Similar to CAB1, genes YIL083C, YKL088W, YGR277C and YDR106C responsible for late CoA biosynthesis turned out as essential. Null mutants could be complemented by their bacterial counterparts coaBC, coaD and coaE, respectively. Comparative expression analyses showed that some CoA biosynthetic genes are weakly de-repressed with ethanol as a carbon source compared with glucose.
Olzhausen
Judith
J
Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt Universität Greifswald, Germany.
Schübbe
Sabrina
S
Schüller
Hans-Joachim
HJ
D000429:Alcohol Oxidoreductases; D000595:Amino Acid Sequence; D003065:Coenzyme A / Q000096:biosynthesis*; D015966:Gene Expression Regulation, Fungal; D019877:Hydroxymethyl and Formyl Transferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D027981:Symporters; D013696:Temperature
C436246:FEN2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D027981:Symporters; D000429:Alcohol Oxidoreductases; C097954:PAN5 protein, S cerevisiae; D019877:Hydroxymethyl and Formyl Transferases; C021477:3-methyl-2-oxobutanoate hydroxymethyltransferase; D017853:Phosphotransferases (Alcohol Group Acceptor); C023088:pantothenate kinase; D010453:Peptide Synthases; C022318:pantothenate synthetase; D003065:Coenzyme A