Topic
Lanosterol
About: Lanosterol is a research topic. Over the lifetime, 1239 publications have been published within this topic receiving 36737 citations. The topic is also known as: (3β)-lanosta-8,24-dien-3-ol & (3β,20R)-lanosta-8,24-dien-3-ol.
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TL;DR: There are two categories of metabolic steps in the pathways for sterol synthesis that were sensitive to inhibition by U18666A and AY-9944 that are located before lanosterol formation and were suppressed only by relatively high concentrations of inhibitors.
49 citations
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TL;DR: Novel three series of benzimidazole scaffold bearing hydrazone, 1,2, 4-triazole and 1,3,4-oxadiazole moieties 1-3, 4a-j, 6a-c and 7 derivatives were designed, synthesized and evaluated for their antimicrobial activity, confirming their antifungal activity and in silico ADME prediction investigations also forecasting the drug-like characters.
49 citations
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TL;DR: A cell-free system has been obtained from Saccharomyces cerevisiae which is capable of efficiently converting lanosterol 1 to a mixture of 4-demethyl sterols, quantitatively the most important identifiable component of which was zymosterol as discussed by the authors.
48 citations
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TL;DR: The compound 2,3;22,23-dioxidosqualene has been found to accumulate in yeast grown in the presence of 10−4m 3β-(β-dimethylaminoethoxy)-androst-5-en-17-one and subsequent removal of the latter compound permits the formation of 24,25-oxidolanosterol and more polar unidentified compounds.
48 citations
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TL;DR: The wheat enzyme was expressed in yeast strains overexpressing different P450 reductases as a fusion with either yeast or plant (sorghum) membrane targeting sequences and the expression level was fivefold reduced, as the modified yeasts did not need supplementation with exogenous ergosterol and grew normally under aerobic conditions.
Abstract: CYP51s form the only family of P450 proteins conserved in evolution from prokaryotes to fungi, plants and mammals. In all eukaryotes, CYP51s catalyse 14α-demethylation of sterols. We have recently isolated two CYP51 cDNAs from sorghum [Bak, S., Kahn, R.A., Olsen, C.E. & Halkier, B.A. (1997) Plant J.11, 191–201] and wheat [Cabello-Hurtado, F., Zimmerlin, A., Rahier, A., Taton, M., DeRose, R., Nedelkina, S., Batard, Y., Durst, F., Pallett, K.E. & Werck-Reichhart, D. (1997) Biophys. Biochem. Res. Commun.230, 381–385]. Wheat and sorghum CYP51 proteins show a high identity (92%) compared with their identity with their fungal and mammalian orthologues (32–39%). Data obtained with plant microsomes have previously suggested that differences in primary sequences reflect differences in sterol pathways and CYP51 substrate specificities between animals, fungi and plants. To investigate more thoroughly the properties of the plant CYP51, the wheat enzyme was expressed in yeast strains overexpressing different P450 reductases as a fusion with either yeast or plant (sorghum) membrane targeting sequences. The endogenous sterol demethylase gene (ERG11) was then disrupted. A sorghum–wheat fusion protein expressed with the Arabidopsis thaliana reductase ATR1 showed the highest level of expression and activity. The expression induced a marked proliferation of microsomal membranes so as to obtain 70 nmol P450·(L culture)−1, with CYP51 representing 1.5% of microsomal protein. Without disruption of the ERG11 gene, the expression level was fivefold reduced. CYP51 from wheat complemented the ERG11 disruption, as the modified yeasts did not need supplementation with exogenous ergosterol and grew normally under aerobic conditions. The fusion plant enzyme catalysed 14α-demethylation of obtusifoliol very actively (Km,app = 197 µm, kcat = 1.2 min−1) and with very strict substrate specificity. No metabolism of lanosterol and eburicol, the substrates of the fungal and mammalian CYP51s, nor metabolism of herbicides and fatty acids was detected in the recombinant yeast microsomes. Surprisingly lanosterol (Ks = 2.2 µm) and eburicol (Ks = 2.5 µm) were found to bind the active site of the plant enzyme with affinities higher than that for obtusifoliol (Ks = 289 µm), giving typical type-I spectra. The amplitudes of these spectra, however, suggested that lanosterol and eburicol were less favourably positioned to be metabolized than obtusifoliol. The recombinant enzyme was also used to test the relative binding constants of two azole compounds, LAB170250F and γ-ketotriazole, which were previously reported to be potent inhibitors of the plant enzyme. The Ks of plant CYP51 for LAB170250F (0.29 µm) and γ-ketotriazole (0.40 µm) calculated from the type-II sp2 nitrogen-binding spectra were in better agreement with their reported effects as plant CYP51 inhibitors than values previously determined with plant microsomes. This optimized expression system thus provides an excellent tool for detailed enzymological and mechanistic studies, and for improving the selectivity of inhibitory molecules.
48 citations