Abstract:
3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) is one of the rate-limiting enzymes in the mevalonate pathway, whose expression level and catalytic activity affect the biosynthesis of terpenes and the derivatives. In this study, a
HMGCR homologous gene
RkHMGCR was cloned from
Rhodosporidium kratochvilovae strain YM25235. Sequence analysis showed that
RkHMGCR contains an open reading frame of 3981 bp, encoding a protein RkHMGCR of 1326 amino acids. Similar to the known HMGCRs, RkHMGCR contains conserved motifs including two conserved substrate-binding sites, two conserved NADP(H)-binding sites and four key amino acid residues involved with catalytic activity, indicating that the
RkHMGCR is a potential new
HMGCR gene.
RkHMGCR was further transformed into YM25235 for over expression. Analysis results showed that the over-expression led to an increase of total carotenoids in the YM25235 by 42.21%, whereas the lipid and fatty acids content were decreased by 28.93% and 20.31%, respectively, which were consistent with the transcription analysis results of some genes involved in carotenoid biosynthesis and fatty acid metabolism. This study can provide references for further research on increasing the content of carotenoids and their specific components in oleaginous red yeast through metabolic engineering.