Identification of a gene encoding a homocitrate synthase isoenzyme of Saccharomyces cerevisiae

Flores

2016

Microbiol Mol Biol Rev

SUMMARYMoonlighting proteins are multifunctional proteins that participate in unrelated biological processes and that are not the result of gene fusion. A certain number of these proteins have been characterized in yeasts, and the easy genetic manipulation of these microorganisms has been useful for a thorough analysis of some cases of moonlighting. As the awareness of the moonlighting phenomenon has increased, a growing number of these proteins are being uncovered. In this review, we present a crop of newly identified moonlighting proteins from yeasts and discuss the experimental evidence that qualifies them to be classified as such. The variety of moonlighting functions encompassed by the proteins considered extends from control of transcription to DNA repair or binding to plasminogen. We also discuss several questions pertaining to the moonlighting condition in general. The cases presented show that yeasts are important organisms to be used as tools to understand different aspects of moonlighting proteins.

Section: Homocitrate Synthase Participates In Dna Repairmentioning

confidence: 99%

The Expanding Landscape of Moonlighting Proteins in Yeasts

Flores

2016

Microbiol Mol Biol Rev

“…The promoters of four other LYS genes, of which the expression is activated by Lys14p, namely genes LYS2 (Morris and Jinks-Robertson, 1991), LYS4 (F. Gamonet and G. Lauquin, personal communication), LYS20 (Ramos et al, 1996) and LYS21 (G. Volckaert, personal communication), were analysed for the presence of similar UAS sequences. They contain three, five, two and one DNA motives, respectively, that closely resemble the UAS identified in LYS1 and LYS9 promoters.…”

Section: Sequence Of S Cerevisiae Lys9 and Lys1 Dna Regionsmentioning

confidence: 99%

“…An intermediate of the pathway, ␣-aminoadipate semialdehyde, acts as coinducer for this activation mechanism (Ramos et al, 1988). In addition, feedback inhibition by lysine of the first step of the pathway, catalysed by two homocitrate synthase isoenzymes (Tucci and Ceci, 1972;Ramos et al, 1996; G. Volckaert, personal communication; F. Ramos and E. Dubois, unpublished observation), modulates the metabolic flux through the pathway and, consequently, the production of ␣-aminoadipate semialdehyde. An extremely weak inhibition of ␣-aminoadipate reductase has also been reported (Ford and Bhattacharjee, 1995).…”

Section: Introductionmentioning

confidence: 99%

A nonameric core sequence is required upstream of the LYS genes of Saccharomyces cerevisiae for Lys14p‐mediated activation and apparent repression by lysine

Becker

Feller

Alami

et al. 1998

Molecular Microbiology

Self Cite

SummaryThe expression of the structural genes for lysine (LYS) biosynthesis is controlled by a pathway-specific regulation mediated by the transcriptional activator Lys14 in the presence of ␣-aminoadipate semialdehyde, an intermediate of the pathway acting as a coinducer. Owing to end product inhibition of the first step of the pathway, excess lysine reduces the production of the co-inducer and causes apparent repression of the LYS genes. Analysis of LYS promoters and insertions within an heterologous reporter gene have allowed the characterization of an upstream activating element (UAS LYS ) able to confer Lys14-and ␣-aminoadipate semialdehyde-dependent activation as well as apparent repression by lysine to another yeast gene. This DNA motif is present as one or several copies in the promoters of at least six LYS genes. The consensus sequence derived from the comparison of the UAS LYS showing the highest activation capacities comprises the nonameric core sequence TCCRNYGGA. The RNY sequence of the 3 bp spacer as well as the presence of flanking AT-rich regions on both sides of the core sequence appear essential for optimal activation. Further evidence that this element is the target of Lys14p was provided by the demonstration that Lys14p binds to UAS LYS in vitro. The binding is independent of the presence of the co-inducer and is not affected by lysine. It depends on the integrity of the putative Zn(II) 2 Cys 6 binuclear cluster contained in the Lys14p.

“…Finally, comparison of the deduced sequences of nifV gene products from various diazotrophs and a gene from Saccharomyces cerevisiae that encodes a putative homocitrate synthase (19) also reveals substantial sequence identity. Homocitrate is a precursor within the S. cerevisiae lysine biosynthetic pathway, and disruption of the nifV-like gene results in both a decrease in crude extract homocitrate synthase activity and a decrease in the lysine pool (13). In the present work we describe the heterologous production, purification, and characterization of NifV from A. vinelandii.…”

mentioning

confidence: 99%

Purification of the Azotobacter vinelandii nifV-encoded homocitrate synthase

1997

The nifV gene product (NifV) from Azotobacter vinelandii was recombinantly expressed at high levels in Escherichia coli and purified. NifV is a homodimer that catalyzes the condensation of acetyl coenzyme A (acetyl-CoA) and ␣-ketoglutarate. Although ␣-ketoglutarate supports the highest level of activity, NifV will also catalyze the condensation of acetyl-CoA and certain other keto acids. E. coli cells in which a high level of nifV expression is induced excrete homocitrate into the growth medium.