S-methyl-L-cysteine sulfoxide (SMCO) is a non-protein sulfur-containing amino acid with a variety of functions. There are few reports on the enzymes catalyzing the biosynthesis of SMCO from S-methyl-L-cysteine (SMC). In this study, the flavin-containing monooxygenase gene derived from Schizosaccharomyces pombe (spfmo) was heterologously expressed in Escherichia coli BL21(DE3) and the enzymatic properties of the expressed protein were analyzed. The optimum catalytic conditions of the recombinant SpFMO were 30 ℃ and pH 8.0, under which the enzyme activity reached 72.77 U/g. An appropriate amount of Mg²⁺ improved the enzyme activity. The enzyme kinetic analysis showed that the K_m and k_cat/K_m of SpFMO on the substrate SMC were 23.89 μmol/L and 61.71 L/(min·mmol), respectively. Under the optimal reaction conditions, the yield of SMCO synthesized from SMC catalyzed by SpFMO was 12.31% within 9 h. This study provides reference for the enzymatic synthesis of SMCO.
Schizosaccharomyces/genetics* ; Escherichia coli/metabolism* ; Recombinant Proteins/metabolism* ; Cysteine/biosynthesis* ; Mixed Function Oxygenases/metabolism* ; Schizosaccharomyces pombe Proteins/metabolism* ; Oxygenases/metabolism* ; Kinetics

Genetic information stored in DNA is accurately copied and transferred to subsequent generations through DNA replication. This process is accomplished through the concerted actions of highly conserved DNA replication components. Epigenetic information stored in the form of histone modifications and DNA methylation, constitutes a second layer of regulatory information important for many cellular processes, such as gene expression regulation, chromatin organization, and genome stability. During DNA replication, epigenetic information must also be faithfully transmitted to subsequent generations. How this monumental task is achieved remains poorly understood. In this review, we will discuss recent advances on the role of DNA replication components in the inheritance of epigenetic marks, with a particular focus on epigenetic regulation in fission yeast. Based on these findings, we propose that specific DNA replication components function as key regulators in the replication of epigenetic information across the genome.
Cdc20 Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Centromere ; metabolism ; Chromatin ; metabolism ; Chromosomal Proteins, Non-Histone ; metabolism ; DNA Replication ; DNA, Fungal ; metabolism ; Epigenesis, Genetic ; Histones ; metabolism ; Schizosaccharomyces ; genetics ; metabolism ; Schizosaccharomyces pombe Proteins ; antagonists & inhibitors ; genetics ; metabolism

This research aimed to study the effect of distillage recycling on ethanol fermentation, the key glycolytic enzymes and cell composition of the self-flocculating yeast. With the self-flocculating yeast SPSC01 and medium composed of 220 g/L glucose, 8 g/L yeast extract and 6 g/L peptone, continuous ethanol fermentation was carried out at the dilution rate of 0.04 h(-1) with a 1.5 L tank bioreactor. Fermentation broth was collected every 3 days, and ethanol and other volatile byproducts were removed by distillation, but the stillage with high boiling byproducts was recycled to prepare the medium instead of fresh water. The system was run for 20 days, during which ethanol and biomass concentrations in the effluent decreased continuously, indicating the significant inhibition of the high boiling byproducts accumulated within the system. Thus, the activities of the key enzymes of the glycolytic pathway: hexokinase, 6-phosphofructose kinase, and pyruvate kinase were analyzed, and it was observed that all of them were inhibited. Furthermore, the biosynthesis of the stress response metabolites glycerol and trehalose was investigated, and it was found that glycerol production that can protect yeast cells against osmotic pressure stress was enhanced, but trehalose biosynthesis that can protect yeast cells against ethanol inhibition was not improved, correspondingly. And in the meantime, the biosynthesis of the major intracellular components proteins and hydrocarbons was adjusted, correspondingly.
Bioreactors ; microbiology ; Ethanol ; metabolism ; Fermentation ; Flocculation ; Glycerol ; metabolism ; Glycolysis ; Hexokinase ; metabolism ; Industrial Microbiology ; methods ; Phosphofructokinase-1 ; metabolism ; Saccharomyces cerevisiae ; enzymology ; genetics ; metabolism ; Schizosaccharomyces ; enzymology ; genetics ; metabolism ; Trehalose ; metabolism ; Triticum ; metabolism ; Zea mays ; metabolism

OBJECTIVEGoal of this study was to test the potential regulatory effects of Vpr on Vif and Vif-mediated degradation of APOBEC3G.

METHODSThe Vpr effect was first tested in a fission yeast RE007 strain that carries a single integrated copy of vpr gene in the chromosome and transformed with a vif-expressing plasmid. Similar tests were also carried out in a muristerone A vpr-inducing HEK293 mammalian cell line that were transfected with the plasmids expressing vif and/or APOBEC3G. Western Blot analyses were used to measure the corresponding protein levels under different experimental conditions.

RESULTSExpression of HIV-1 vpr appears to enhance the protein levels of Vif both in fission yeast and mammalian cells. A similar enhancement effect of APOBEC3G by Vpr was also detected in mammalian cells. Interestingly, however, the increased Vif protein level by Vpr did not result in more APOBEC3G degradation than without Vpr, indicating a potential regulatory effect of Vpr on Vif-mediated proteolysis of APOBEC3G.

CONCLUSIONTo our knowledge, this is the first report describing a potentially conserved and regulatory effect of HIV-1 Vpr on Vif and Vif-mediated protein degradation of APOBEC3G.

APOBEC-3G Deaminase ; Animals ; Cell Line ; Cytidine Deaminase ; biosynthesis ; metabolism ; Gene Expression ; Gene Products, vif ; biosynthesis ; metabolism ; Gene Products, vpr ; metabolism ; HIV-1 ; Humans ; Schizosaccharomyces ; genetics

One pair of primers were designed and synthesized on the base of the cDNA sequence encoding Schizosaccharomyces pombe N-glycanase reported on the GenBank. The cDNA sequence encoding Peptide N-glycanase was cloned from the Schizosaccharomyces pombe by RT-PCR. And then the RT-PCR product was cloned into the expression vector pET-15b. The expression vector pET-15b(+)/Png1p was transformed into E. coli BL21(DE3). The results showed that the relative molecular weight of the enzyme was determined to be approximately 39 kD using SDS-PAGE. The expression products after induction and purification can catalyze the cleavage of N-linked oligosaccharides from glycoprotein coped with heat, but have no action on the native glycoprotein with the help of DTT. The percentage of deglycosylated RNase B treated with equate Png1p in different reaction temperature, pH, concentration of DTT and denatured temperature showed that the optimum temperature, the optimum pH is 30 degrees C; the optimum concentration of DTT is 10 mmol/L and the optimum denatured temperature is 100 degrees C.
Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Glycosylation ; Hydrogen-Ion Concentration ; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase ; biosynthesis ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; Schizosaccharomyces ; enzymology ; genetics ; Temperature

The viral spike protein is the main surface antigen of the coronavirus, and it could be useful in the research of clinical diagnosis, SARS vaccine and the structure biology.According to the analysis of the main antigen of the SARS spike protein, 5 fragments of the whole spike gene were cloned, and ligated to the vector pNMT1. Through electroporation transformantion to TCP1, the recombinant S. pombe strains capable of expressing the 5 fragments were constructed. SDS-PAGE or Western blot analysis of the induced expression products demonstrated that the 5 recombinant proteins were expressed in the fission yeast respectively.
Cloning, Molecular ; Electroporation ; Membrane Glycoproteins ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; SARS Virus ; genetics ; Schizosaccharomyces ; genetics ; metabolism ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; biosynthesis ; genetics