National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
CUG Codon in Pathogenic Yeasts of the Genus Candida
Marečková, Lucie ; Heidingsfeld, Olga (advisor) ; Půta, František (referee)
2. Abstract In many Candida species the standard leucine CUG codon is translated as a serine, although not in 100% cases. This dual specifity of the CUG codon has evolved through a mechanism that required codon ambiguity mediated by a unique tRNACAG, which is in vitro aminoacylated more often by serine than by leucine. This codon ambiguity has been tolerated for more than 170 million years. The explanation at least for now is that the CUG codon reassignment could have generated genetic diversity that facilitated occurrence of new phenotypes resistant to stress. Beside this, an important step was to reduce negative impact of the codon ambiguity by crucial mutations in the structure of the ser-tRNACAG. Candida species became a valuable experimental model for elucidation of the genetic code changes. While consequences of the CUG codon reassignment have been extensively studied in Candida albicans, this topic has not yet been addressed in Candida parapsilosis. Solving the structure of C. parapsilosis secreted proteinase Sapp1p provided a tool to carry out a "case study" of possible effects of the CUG codon ambiguity. The SAPP1 gene contains one CUG codon, and the respective serine is located on the loop in the close proximity of the active site of the proteinase.
CUG Codon in Pathogenic Yeasts of the Genus Candida
Marečková, Lucie ; Půta, František (referee) ; Heidingsfeld, Olga (advisor)
2. Abstract In many Candida species the standard leucine CUG codon is translated as a serine, although not in 100% cases. This dual specifity of the CUG codon has evolved through a mechanism that required codon ambiguity mediated by a unique tRNACAG, which is in vitro aminoacylated more often by serine than by leucine. This codon ambiguity has been tolerated for more than 170 million years. The explanation at least for now is that the CUG codon reassignment could have generated genetic diversity that facilitated occurrence of new phenotypes resistant to stress. Beside this, an important step was to reduce negative impact of the codon ambiguity by crucial mutations in the structure of the ser-tRNACAG. Candida species became a valuable experimental model for elucidation of the genetic code changes. While consequences of the CUG codon reassignment have been extensively studied in Candida albicans, this topic has not yet been addressed in Candida parapsilosis. Solving the structure of C. parapsilosis secreted proteinase Sapp1p provided a tool to carry out a "case study" of possible effects of the CUG codon ambiguity. The SAPP1 gene contains one CUG codon, and the respective serine is located on the loop in the close proximity of the active site of the proteinase.

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