Saccharomyces cerevisiae inhibitors

Feedback inhibition of amino acid transporters by amino acids synthesized by the cells might be responsible for the well known fact that blocking protein synthesis by cycloheximide in Saccharomyces cerevisiae inhibits the uptake of most amino acids [56]. Indeed, under these conditions, endogenous amino acids continue to accumulate. This situation, which precludes studying amino acid transport in yeast in the presence of inhibitors of protein synthesis, is very different from that observed in bacteria, where amino acid uptake is commonly measured in the presence of chloramphenicol in order to isolate the uptake process from further metabolism of accumulated substances. In yeast, when nitrogen starvation rather than cycloheximide is used to block protein synthesis, this leads to very high uptake activity. This fact supports the feedback inhibition interpretation of the observed cycloheximide effect. 

Cohen-Fix O, Peters JM, Kirschner MW, KoshlandD 1996 Anaphase initiation in Saccharomyces cerevisiae is controlled by the APC-dependent degradation of the anaphase inhibitor Pdslp. Genes Dev 10 3081-3093... 

The bioreduction of carbonyl compounds with reductases has been exploited for many years, especially in the case of ketones, with baker s yeast Saccharomyces cerevisiae) being the most popular biocatalyst [45]. For instance, yeast treatment of 3-chloropropiophenone affords the expected (lS)-3-chloro-l-phenylpropan-l-ol, which was treated with trifluorocresol in tertrahydrofuran in the presence of tri-phenylphosphine and diethyl azodicarboxylate at room temperature to give (3R)-l-chloro-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propane and the later reaction with methylamine leads to (R)-fluoxetine that is an important serotonin uptake inhibitor (Scheme 10.19) [46]. 

Mendenhall, M. D. (1993). An inhibitor of p34CDC28 protein kinase activity from Saccharomyces cerevisiae. Science 259,216-9. 

Lee DH, Goldberg AL (1996) Selective inhibitors of the proteasome-dependent and vacuolar pathways of protein degradation in Saccharomyces cerevisiae. J Biol Chem 271 27280-27284... 

Almeida JRM, Modig T, Petersson A, Hahn-Hagerdal B, Liden G, Gorwa-Grauslund MF. 2007. Increased tolerance and conversion of inhibitors in lignocellulosic hydrolysates by Saccharomyces cerevisiae. J Chem Technol Biotech 82 340-349. 

VH Brophy, J Vasquez, RG Nelson, JR Fomey, A Rosowsky, CH Sibley. Identification of Cryptosporidium parvum dihydrofolate reductase inhibitors by complementation in Saccharomyces cerevisiae. Antimicrob Agents Chemother 44 1019-1028, 2000. 

The fermentation inhibitors include furan aldehydes, aliphatic acids, and phenolic compounds. The furan aldehydes, furfural, and hydroxymethyl furfural (HMF), are formed from pentoses and hexoses, respectively (4,5). Several studies indicate that furfural inhibits Saccharomyces cerevisiae, at least when present in high concentrations (6-10). HMF has a similar effect (11,12). 

Two different strains of Saccharomyces cerevisiae were used CBS 8066 (Centralbureau voor Schimmelcultures, Delft, The Netherlands) and TMB 3000 (Division of Applied Microbiology, Lund University, Sweden). TMB 3000 is a strain originally isolated from spent sulfite liquor, and therefore it has a high tolerance to inhibitors. The strains were maintained on agar plates (20 g/L of agar, 20 g/L of soya peptone, 20 g/L of glucose, and 10 g/L of yeast extract). Before the fermentations, inoculum cultures were grown in 250-mL conical E-flasks. The flasks were placed in a shaker bath (30°C, 140 rpm) for 24 h. 

Figure 8.24 The effect of inhibitors on the content of certain PolyP fractions in Saccharomyces cerevisiae cells under phosphate overplus (Trilisenko et al., 2003). (A) PolyP in Pj-starved cells (B-G) PolyP in cells grown at 2 h after re-inoculation on the complete medium (phosphate overplus) (B) control conditions (C) 10 mg mT1 of cycloheximide (D) 10 //M FCCP (E) 20 //M FCCP (F) 250 /-iM iodacetamide (G) 50 nM bafilomycin A. PolyP fractions (1) PolyP(I) (2) PolyP(H) (3) PolyP(III) (4) PolyP(IV) (5) PolyP(V).

L. V. Trilisenko, N. A. Andreeva, T. V. Kulakovskaya, V. M. Vagabov and I. S. Kulaev (2003). Effect of inhibitors on polyphosphate metabolism in the yeast Saccharomyces cerevisiae under hypercompensation conditions. Biochemistry (Moscow), 68, 577-581. 

K. D. Wittrup. Secretion effidency in Saccharomyces cerevisiae of bovine pancreatic trypsin inhibitor mutants lacking disulfide bonds is correlated with thermodynamic stability. Biochemistry (1998) 37(5) 1264-73. 

The X-ray structures of the bci complexes from bovine heart, chicken heart, and the yeast Saccharomyces cerevisiae have been determined at 3.0 - 2.3 A resolution [3-6] therefore, it is possible to explore the interaction between the complex and quinones and inhibitors at molecular level. First, we will give an overview of essential structural features of the bci complex. As the non-catalytic subunits are not involved in the coordination of the redox centers or the formation of quinone binding sites, only the structure of the three eatalytic subunits will be discussed in the following section (Figure 3) for a more detailed description see [19]. In order to avoid confusion, the residue numbering of the yeast bci complex will be used even if other organisms have been studied. 

The membrane-bound archaeal ATPases have attracted considerable interest since patterns of inhibitor sensitivity, subunit structure, and amino-acid sequence homologies suggest a close relationship to the V-type ATPases [3,41]. In addition, the membrane-bound ATPases from S. acidocaldarius, H. salinarium (halobium), Methanosarcina barken, and the V-type ATPase from Saccharomyces cerevisiae are immunologically related [42]. 

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