Аннотация:Abstract This review is a first attempt to systematize data on the potential of
transgenic Y. lipolytica to catalyze diverse reactions of steroid transformation. The
yeast Y. lipolytica was tested as host for P450-catalyzed biotransformation of
steroids, including the mammalian P450scc system (three components) and/or the
two-component P450c17 system, being functionally active with yeast NADPHP450
reductase (CPR). New strategies for the construction of recombinant
Y. lipolytica strains containing several expression cassettes containing heterologous
cDNA (up to 4, in five vectors) under control of the isocitrate lyase (ICL1) promoter
have been developed. Characteristics of recombinant Y. lipolytica strains functionally
expressing the P450scc system and/or P450c17, being functionally active with
yeast NADPH-P450 reductase (YlCPR), are presented.
Functional expression of P450 systems in yeasts was proved by biotransformation
of cholesterol (Cho) or by 17α-hydroxylation of progesterone (Pro) or pregnenolone
(Pre). Strains coexpressing the P450scc system and P450c17 exhibited a
high biotransformation capacity of Pro into 17α-hydroxyprogesterone (17HPro);
the conversion of Cho to Pre and 17α-hydroxypregnenolone occurred rather slowly.
For selected P450c17 expressing Y. lipolytica strains, the cultivation conditions(induction, bioconversion) were optimized for high product yield (up to 95 %
17HPro) and reduction of the diol side-product formation from 19–22 % to
1–2 % without gene destruction.
The results obtained could be used for elaboration of new biotechnological
approaches with using recombinant yeast strains for synthesis of pharmaceutically
active steroids and for screening of compounds which inhibit the P450c17 enzyme
activity, playing important roles in the development of hormonal carcinogenesis.