title: Functional analysis of YCL09C: evidence for a role as the regulatory subunit of acetolactate synthase.
abstract: We have analysed the function of the open reading frame (ORF) YCL09C. The deletion of this ORF from chromosome III does not affect the physiology of the corresponding yeast strain enough to give a distinct phenotype. Nevertheless a computational analysis reveals high homology between this ORF and the enterobacterial genes encoding the regulatory subunit of acetolactate synthase. We have therefore tested the possibility that yc109cp is the regulatory subunit of yeast acetolactate synthase by in vitro enzymatic analysis. The acetolactate synthase was previously shown to be retroinhibited by its final product valine. In Escherichia coli this retro-control is assured by the regulatory subunit. Using a yeast strain carrying a complete deletion of YCL09C, we have observed the loss of such retro-inhibition. These results together with the computational predictions show that YCL09C encodes the regulatory subunit of yeast acetolactate synthase.
authors.affiliation: Centre de Génétique Moléculaire du CNRS, Laboratoire Propre Associé à l'Université Pierre et Marie Curie, Gif-sur-Yvette, France.
authors.forename: C
authors.initials: C
authors.lastname: Cullin
authors.forename: A
authors.initials: A
authors.lastname: Baudin-Baillieu
authors.forename: E
authors.initials: E
authors.lastname: Guillemet
authors.forename: O
authors.initials: O
authors.lastname: Ozier-Kalogeropoulos
mesh_terms: D000093:Acetoin / Q000378:metabolism; D000095:Acetolactate Synthase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D004247:DNA / Q000235:genetics; D001330:Electronic Data Processing; D004755:Enterobacteriaceae / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D007532:Isoleucine / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014633:Valine / Q000378:metabolism / Q000494:pharmacology
chemical_list: D007532:Isoleucine; D004247:DNA; D000093:Acetoin; D000095:Acetolactate Synthase; D014633:Valine