TY - JOUR
T1 - Sterol 24-C-methyltransferase
T2 - An enzymatic target for the disruption of ergosterol biosynthesis and homeostasis in Cryptococcus neoformans
AU - Nes, W. David
AU - Zhou, Wenxu
AU - Ganapathy, Kulothungan
AU - Liu, Jia Lin
AU - Vatsyayan, Rit
AU - Chamala, Swetha
AU - Hernandez, Keven
AU - Miranda, Mayra
N1 - Funding Information:
This research was supported in part by the grants from the National Science Foundation (MCB-0417436) and the Welch Foundation (D-1276) to WDN.
PY - 2009/1/15
Y1 - 2009/1/15
N2 - Growth of Cryptococcus neoformans was inhibited by nine nitrogen and sulfur-containing sterols with a heteroatom positioned at C3, C7, C24, C25 or C32 in the lanostane frame. Analysis of the sterol composition of control and treated cells by GC-MS and 1H NMR has proven that the C-methylation reaction catalyzed by the sterol 24-C-methyltransferase (24-SMT) is the crucial first step in a kinetically favored pathway that fails to include obtusifoliol or zymosterol as intermediates. Cultures fed [methyl-2H3]methionine led to two deuterium atoms into each of the newly biosynthesized sterols forming a route lanosterol, eburicol (24(28)-methylene-24,25-dihydrolanosterol), 32-noreburicol and ergost-7-enol to ergosterol. Examination of the substrate specificity of a soluble 24-SMT from C. neoformans showed lanosterol to be the optimal acceptor molecule. Incubation with the test compounds generated induced amounts of lanosterol, eburicol or 32-noreburicol concurrent with a decrease of ergosterol. Among them 24(R,S),25-epiminolanosterol (inhibitor of 24-SMT) showed the most potent in vitro antifungal activity comparable to those of itraconazole (inhibitor of the 14-demethylase). Taken together, these data indicate that treatment with substrate-based inhibitors of 24-SMT, a catalyst not found in humans, can disrupt ergosterol homeostasis involved with fungal growth and therefore these compounds can provide leads for rational drug design of opportunistic pathogens.
AB - Growth of Cryptococcus neoformans was inhibited by nine nitrogen and sulfur-containing sterols with a heteroatom positioned at C3, C7, C24, C25 or C32 in the lanostane frame. Analysis of the sterol composition of control and treated cells by GC-MS and 1H NMR has proven that the C-methylation reaction catalyzed by the sterol 24-C-methyltransferase (24-SMT) is the crucial first step in a kinetically favored pathway that fails to include obtusifoliol or zymosterol as intermediates. Cultures fed [methyl-2H3]methionine led to two deuterium atoms into each of the newly biosynthesized sterols forming a route lanosterol, eburicol (24(28)-methylene-24,25-dihydrolanosterol), 32-noreburicol and ergost-7-enol to ergosterol. Examination of the substrate specificity of a soluble 24-SMT from C. neoformans showed lanosterol to be the optimal acceptor molecule. Incubation with the test compounds generated induced amounts of lanosterol, eburicol or 32-noreburicol concurrent with a decrease of ergosterol. Among them 24(R,S),25-epiminolanosterol (inhibitor of 24-SMT) showed the most potent in vitro antifungal activity comparable to those of itraconazole (inhibitor of the 14-demethylase). Taken together, these data indicate that treatment with substrate-based inhibitors of 24-SMT, a catalyst not found in humans, can disrupt ergosterol homeostasis involved with fungal growth and therefore these compounds can provide leads for rational drug design of opportunistic pathogens.
KW - Amphotericin B
KW - Antifungal agent
KW - Ergosterol
KW - Ergosterol biosynthesis inhibitor
KW - Itraconazole
KW - Lanosterol
KW - Membrane
KW - Sterol methyl transferase
UR - http://www.scopus.com/inward/record.url?scp=58049098654&partnerID=8YFLogxK
U2 - 10.1016/j.abb.2008.11.003
DO - 10.1016/j.abb.2008.11.003
M3 - Article
C2 - 19014901
AN - SCOPUS:58049098654
SN - 0003-9861
VL - 481
SP - 210
EP - 218
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -