A DEVIATION FRONT THE UNIVERSAL GENETIC-CODE IN CANDIDA-MALTOSA AND CONSEQUENCES FOR HETEROLOGOUS EXPRESSION OF CYTOCHROMES P450 52A4 AND 52A5 IN SACCHAROMYCES-CEREVISIAE

作者：ZIMMER T; SCHUNCK WH

来源：Yeast, 1995, 11(1): 33-41.

DOI：10.1002/yea.320110105

• CANDIDA MALTOSA
• CODON USAGE
• CYTOCHROME P450
• PROTEIN DEGRADATION

We demonstrate that serine instead of leucine is specified by the CUG codon in the yeast Cannida maltosa. Evidence for this deviation from the universal genetic code was obtained by means of in vitro translation experiments. Depending on the cell-free system used, either serine, in the C. maltosa system, or leucine, in the control with the conventional wheat germ system, was found to be incorporated into the translation products of articia CUG-containing mRNAs. Moreover, we were able to transfer the non-universal decoding of CUG to the wheat germ system by adding a tRNA fraction isolated from C. maltosa. This finding indicates the presence in C. maltosa of an unusual serine tRNA that recognizes CUG. As a consequence of the altered genetic code, expression in Saccharomyces cerevisiae of C. maltosa cytochrome P450 genes required an exchange of their CTG triplets by TCT encoding serine in order to produce the authentic proteins. In contrast, heterologous expression of the original C. maltosa genes resulted in the formation of still active but unstable enzymes probably subject to selective proteolysis in the host cells.

• 出版日期1995-1