Search results for "saccharomyces"

Alteration in membrane fluidity and lipid composition, and modulation of H(+)-ATPase activity in Saccharomyces cerevisiae caused by decanoic acid.

1996

Decanoic acid, a lipophilic agent, inhibited in vitro the plasma membrane H+-ATPase of Saccharomyces cerevisiae grown in YPD medium. Conversely, when decanoic acid (35 μM) was present in the growth medium, the measured H+-ATPase activity was four times higher than that of control cells. K m, and pH and orthovanadate sensitivity were the same for the two growth conditions, which indicated that H+-ATPase activation was not due to conformational changes in the enzyme. The activation process was not entirely reversible which showed that plasma membrane H+-ATPase activation is due to several mechanisms. 1,6-diphenyl-1,3,5-hexatriene anisotropy performed on protoplasts from cells grown in YPD rev…

Translational fusion to the Pir4 cell wall protein as a general and efficient method for cell surface immobilization or growth medium secretion of re…

2008

Synthesis and Assembly of Wall Polymers on Regenerating Yeast Protoplasts

1983

Accumulation of chitin and glucan on S. cerevisiae and C. albicans protoplasts begins shortly after resuspension in the regeneration medium, and mannoprotein molecules also appear retained by the regenerating wall after 30–60 minutes in S. cerevisiae or after a longer lag period in C. albicans. Nevertheless, a considerable fraction of the synthesized mannoproteins, which in SDS-acrylamide gels exhibit a different pattern from that of wall mannoproteins of cells, are still released to the growth medium during at least eight hours. De novo synthesis of chitin synthase, but not of glucan synthase, is observed in S. cerevisiae from about 30 minutes after initiation of the regeneration process. …

Allelic variants of hexose transporter Hxt3p and hexokinases Hxk1p/Hxk2p in strains ofSaccharomyces cerevisiaeand interspecies hybrids

2015

The transport of sugars across the plasma membrane is a critical step in the utilization of glucose and fructose by Saccharomyces cerevisiae during must fermentations. Variations in the molecular structure of hexose transporters and kinases may affect the ability of wine yeast strains to finish sugar fermentation, even under stressful wine conditions. In this context, we sequenced and compared genes encoding the hexose transporter Hxt3p and the kinases Hxk1p/Hxk2p of Saccharomyces strains and interspecies hybrids with different industrial usages and regional backgrounds. The Hxt3p primary structure varied in a small set of amino acids, which characterized robust yeast strains used for the p…

Glutathione metabolism and heavy metal detoxification in Schizosaccharomyces pombe

1991

Sixty glutathione-deficient mutants (gsh −) of Schizosaccharomyces pombe have been isolated by their resistance towards the mutagen N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) and their sensitivity to the heavy metal Cadmium (Cd). fifty-three mutants show glutathione contents of less than 5% compared with the wild-type. The residual glutathione contents correlate with the resistance to MNNG, with the sensitivity to Cd and with the growth rate in minimal medium. The gsh −, Cd-sensitive (Cd s) mutants also show sensitivity to other heavy metals. Wild-type strains, but not the gsh − mutants, are able to excrete the heavy metal, very likely as a sulfide-containing compound. This inability of th…

Functional analysis of the cysteine residues and the repetitive sequence ofSaccharomyces cerevisiaePir4/Cis3: the repetitive sequence is needed for b…

2003

Identification of PIR/CIS3 gene was carried out by amino-terminal sequencing of a protein band released by β-mercaptoethanol (β-ME) from S. cerevisiae mnn9 cell walls. The protein was released also by digestion with β-1,3-glucanases (laminarinase or zymolyase) or by mild alkaline solutions. Deletion of the two carboxyterminal Cys residues (Cys214-12aa-Cys227-COOH), reduced but did not eliminate incorporation of Pir4 (protein with internal repeats) by disulphide bridges. Similarly, site-directed mutation of two other cysteine amino acids (Cys130Ser or Cys197Ser) failed to block incorporation of Pir4; the second mutation produced the appearance of Kex2-unprocessed Pir4. Therefore, it seems th…

Comparative analysis of the coordinated motion of Hsp70s from different organelles observed by single-molecule three-color FRET.

2021

Cellular function depends on the correct folding of proteins inside the cell. Heat-shock proteins 70 (Hsp70s), being among the first molecular chaperones binding to nascently translated proteins, aid in protein folding and transport. They undergo large, coordinated intra- and interdomain structural rearrangements mediated by allosteric interactions. Here, we applied a three-color single-molecule Forster resonance energy transfer (FRET) combined with three-color photon distribution analysis to compare the conformational cycle of the Hsp70 chaperones DnaK, Ssc1, and BiP. By capturing three distances simultaneously, we can identify coordinated structural changes during the functional cycle. Be…

O-Ribosyl-phosphate purine as a constant modified nucleotide located at position 64 in cytoplasmic initiator tRNAsMetof yeasts

1991

The unknown modified nucleotide G*, isolated from both Schizosaccharomyces pombe and Torulopsis utilis initiator tRNAs(Met), has been identified as an O-ribosyl-(1"----2')-guanosine-5"-phosphate, called Gr(p), by means of HPLC, UV-absorption, mass spectrometry and periodate oxidation procedures. By comparison with the previously published structure of Ar(p) isolated from Saccharomyces cerevisiae initiator tRNA(Met), the (1"----2')-glycosidic bond in Gr(p) has been postulated to have a beta-spatial conformation. The modified nucleotide Gr(p) is located at position 64 in the tRNA(Met) molecules, i.e. at the same position as Ar(p). Since we have also characterized Gr(p) in Candida albicans ini…

Relationships between kinetic constants and the amino acid composition of enzymes from the yeast Saccharomyces cerevisiae glycolysis pathway

2012

The kinetic models of metabolic pathways represent a system of biochemical reactions in terms of metabolic fluxes and enzyme kinetics. Therefore, the apparent differences of metabolic fluxes might reflect distinctive kinetic characteristics, as well as sequence-dependent properties of the employed enzymes. This study aims to examine possible linkages between kinetic constants and the amino acid (AA) composition (AAC) for enzymes from the yeast Saccharomyces cerevisiae glycolytic pathway. The values of Michaelis-Menten constant (K M), turnover number (k cat), and specificity constant (k sp = k cat/K M) were taken from BRENDA (15, 17, and 16 values, respectively) and protein sequences of nine…

Identification of the 3-amino-3-carboxypropyl (acp) transferase enzyme responsible for acp3U formation at position 47 in Escherichia coli tRNAs

2019

AbstracttRNAs from all domains of life contain modified nucleotides. However, even for the experimentally most thoroughly characterized model organism Escherichia coli not all tRNA modification enzymes are known. In particular, no enzyme has been found yet for introducing the acp3U modification at position 47 in the variable loop of eight E. coli tRNAs. Here we identify the so far functionally uncharacterized YfiP protein as the SAM-dependent 3-amino-3-carboxypropyl transferase catalyzing this modification and thereby extend the list of known tRNA modification enzymes in E. coli. Similar to the Tsr3 enzymes that introduce acp modifications at U or m1Ψ nucleotides in rRNAs this protein conta…