Enhancement of Galactose Uptake from Kappaphycus alvarezii Hydrolysate Using Saccharomyces cerevisiae Through Overexpression of Leloir Pathway Genes

2020 ◽  
Author(s):  
In Yung Sunwoo ◽  
Pailin Sukwong ◽  
Yu Rim Park ◽  
Deok Yeol Jeong ◽  
Soo Rin Kim ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kappaphycus Alvarezii ◽  
Leloir Pathway

Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae

1991 ◽  
Vol 11 (11) ◽  
pp. 5454-5461
Author(s):  
J Meyer ◽  
A Walker-Jonah ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Regulatory Function ◽  
Bifunctional Protein ◽  
Leloir Pathway ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Gal1 Gene ◽  
Galactokinase Activity ◽  
Negative Mutant

We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.

scholarly journals Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (11) ◽  
pp. 5454-5461 ◽  
Author(s):  
J Meyer ◽  
A Walker-Jonah ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Regulatory Function ◽  
Bifunctional Protein ◽  
Leloir Pathway ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Gal1 Gene ◽  
Galactokinase Activity ◽  
Negative Mutant

We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.

scholarly journals The Molecular Architecture of Galactose Mutarotase/UDP-Galactose 4-Epimerase from Saccharomyces cerevisiae

2005 ◽  
Vol 280 (23) ◽  
pp. 21900-21907 ◽  
Author(s):  
James B. Thoden ◽  
Hazel M. Holden
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Active Sites ◽  
Polypeptide Chain ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Dual Function ◽  
Molecular Architecture ◽  
Single Polypeptide Chain ◽  
Leloir Pathway ◽  
The Individual

The metabolic pathway by which β-d-galactose is converted to glucose 1-phosphate is known as the Leloir pathway and consists of four enzymes. In most organisms, these enzymes appear to exist as soluble entities in the cytoplasm. In yeast such as Saccharomyces cerevisiae, however, the first and last enzymes of the pathway, galactose mutarotase and UDP-galactose 4-epimerase, are contained within a single polypeptide chain referred to as Gal10p. Here we report the three-dimensional structure of Gal10p in complex with NAD+, UDP-glucose, and β-d-galactose determined to 1.85-Å resolution. The enzyme is dimeric with dimensions of ∼91 Å × 135 Å × 108 Å and assumes an almost V-shaped appearance. The overall architecture of the individual subunits can be described in terms of two separate N- and C-terminal domains connected by a Type II turn formed by Leu-357 to Val-360. The first 356 residues of Gal10p fold into the classical bilobal topology observed for all other UDP-galactose 4-epimerases studied thus far. This N-terminal domain contains the binding sites for NAD+ and UDP-glucose. The polypeptide chain extending from Glu-361 to Ser-699 adopts a β-sandwich motif and harbors the binding site for β-d-galactose. The two active sites of Gal10p are separated by over 50 Å. This investigation represents the first structural analysis of a dual function enzyme in the Leloir pathway.

scholarly journals Energetic limits to metabolic flexibility: responses of Saccharomyces cerevisiae to glucose–galactose transitions

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1340-1350 ◽  
Author(s):  
J. van den Brink ◽  
M. Akeroyd ◽  
R. van der Hoeven ◽  
J. T. Pronk ◽  
J. H. de Winde ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Energy Charge ◽  
Metabolic Flexibility ◽  
Energy Status ◽  
Anaerobic Conditions ◽  
Leloir Pathway ◽  
Chemostat Cultures ◽  
Galactose Utilization ◽  
Intracellular Energy ◽  
Adenosine Nucleotide

Glucose is the favoured carbon source for Saccharomyces cerevisiae, and the Leloir pathway for galactose utilization is only induced in the presence of galactose during glucose-derepressed conditions. The goal of this study was to investigate the dynamics of glucose–galactose transitions. To this end, well-controlled, glucose-limited chemostat cultures were switched to galactose-excess conditions. Surprisingly, galactose was not consumed upon a switch to galactose excess under anaerobic conditions. However, the transcripts of the Leloir pathway were highly increased upon galactose excess under both aerobic and anaerobic conditions. Protein and enzyme-activity assays showed that impaired galactose consumption under anaerobiosis coincided with the absence of the Leloir-pathway proteins. Further results showed that absence of protein synthesis was not caused by glucose-mediated translation inhibition. Analysis of adenosine nucleotide pools revealed a fast decrease of the energy charge after the switch from glucose to galactose under anaerobic conditions. Similar results were obtained when glucose–galactose transitions were analysed under aerobic conditions with a respiratory-deficient strain. It is concluded that under fermentative conditions, the energy charge was too low to allow synthesis of the Leloir proteins. Hence, this study conclusively shows that the intracellular energy status is an important factor in the metabolic flexibility of S. cerevisiae upon changes in its environment.

scholarly journals Improvement of Galactose Uptake in Saccharomyces cerevisiae through Overexpression of Phosphoglucomutase: Example of Transcript Analysis as a Tool in Inverse Metabolic Engineering

2005 ◽  
Vol 71 (11) ◽  
pp. 6465-6472 ◽  
Author(s):  
Christoffer Bro ◽  
Steen Knudsen ◽  
Birgitte Regenberg ◽  
Lisbeth Olsson ◽  
Jens Nielsen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metabolic Engineering ◽  
Reference Strain ◽  
Transcriptional Response ◽  
Transcript Analysis ◽  
Recombinant Strains ◽  
Leloir Pathway ◽  
Uptake Rates ◽  
Genes Encoding ◽  
Sugar Phosphates

ABSTRACT Through genome-wide transcript analysis of a reference strain and two recombinant Saccharomyces cerevisiae strains with different rates of galactose uptake, we obtained information about the global transcriptional response to metabolic engineering of the GAL gene regulatory network. One of the recombinant strains overexpressed the gene encoding the transcriptional activator Gal4, and in the other strain the genes encoding Gal80, Gal6, and Mig1, which are negative regulators of the GAL system, were deleted. Even though the galactose uptake rates were significantly different in the three strains, we surprisingly did not find any significant changes in the expression of the genes encoding the enzymes catalyzing the first steps of the pathway (i.e., the genes encoding Gal2, Gal1, Gal7, and Gal10). We did, however, find that PGM2, encoding the major isoenzyme of phosphoglucomutase, was slightly up-regulated in the two recombinant strains with higher galactose uptake rates. This indicated that PGM2 is a target for overexpression in terms of increasing the flux through the Leloir pathway, and through overexpression of PGM2 the galactose uptake rate could be increased by 70% compared to that of the reference strain. Based on our findings, we concluded that phosphoglucomutase plays a key role in controlling the flux through the Leloir pathway, probably due to increased conversion of glucose-1-phosphate to glucose-6-phosphate. This conclusion was supported by measurements of sugar phosphates, which showed that there were increased concentrations of glucose-6-phosphate, galactose-6-phosphate, and fructose-6-phosphate in the strain construct overexpressing PGM2.

scholarly journals Development of Novel Bread by Combining Seaweed Kappaphycus alvarezii from Sri Lanka and Saccharomyces cerevisiae Isolated from Nectarine

2019 ◽  
Vol 9 (5) ◽  
Author(s):  
Noriko Komatsuzaki ◽  
Sayoko Arai ◽  
Shinobu Fujihara ◽  
Jun Shima ◽  
Rathnayake Saman Wijesekara ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sri Lanka ◽  
Kappaphycus Alvarezii

scholarly journals IMP1/imp1: A GENE INVOLVED IN THE NUCLEO-MITOCHONDRIAL CONTROL OF GALACTOSE FERMENTATION IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1981 ◽  
Vol 97 (1) ◽  
pp. 27-44
Author(s):  
A A Algeri ◽  
L Bianchi ◽  
A M Viola ◽  
P P Puglisi ◽  
N Marmiroli
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Gene ◽  
Genetic Determinant ◽  
Mitochondrial Inhibitors ◽  
Leloir Pathway ◽  
Induction Of Enzymes ◽  
Gal Genes ◽  
Galactose Utilization ◽  
Respiratory Deficient

ABSTRACT In some strains of Saccharomyces cerevisiae, the induction of enzymes of the Leloir pathway, galactose fermentation and growth on galactose depend on mitochondrial function; mitochondrial dependence is elicited through the recessive allele imp1 of the nuclear gene IMP1. The genetic element IMP1 is not allelic to any of the known GAL genes; IMP1 strains can grow on and ferment galactose in respiratory-deficient (RD) condition or in the presence of the mitochondrial inhibitors ethidium bromide and erythromycin; whereas, imp1 strains can grow on and ferment galactose only in respiratory-sufficient (RS) condition. The imp1 elicited mitochondrial dependence apparently involves regulation of the synthesis of the galactose catabolizing enzymes and synthesis of the galactose specific permease. IMP1 is not the only genetic determinant that elicits an interaction of the mitochondrion and the expression of the Gal system; the GAL3 gene, whose role in galactose utilization is demonstrated by the long-term adaptation phenotype of gal3 RS mutants, gives rise to a noninducible phenotype in RD condition or in the presence of mitochondrial inhibitors.

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