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Candida CYP52: Alkane and fatty acid metabolism. / Claire Louise Price

Swansea University Author: Claire Louise, Price

Abstract

Cytochromes P450 are a superfamily of haem-thiolate proteins found in all kingdoms of life. To date 11294 enzymes have been identified and have been shown to be involved in the metabolism of a wide variety of substrates, including hydrocarbons and xenobiotics. In yeast and fungi the hydroxylation of...

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Published: 2012
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42696
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Abstract: Cytochromes P450 are a superfamily of haem-thiolate proteins found in all kingdoms of life. To date 11294 enzymes have been identified and have been shown to be involved in the metabolism of a wide variety of substrates, including hydrocarbons and xenobiotics. In yeast and fungi the hydroxylation of alkanes is associated with a family of cytochromes P450 enzymes known as CYP52s. These enzymes are involved in the terminal hydroxylation of long-chain alkanes resulting in the production of alcohols, which can be further converted to form fatty acids and diacids. In vivo such hydrocarbons can be subjected to beta-oxidation for use in growth. Alternatively, the products formed by CYP52 catalysed hydroxylation in vitro can be used in biotechnological applications. They can be used as platform chemicals in the production of a number of industrial products, including plastics, fragrances and antibiotics. The p-oxidation of fatty acids has been less well documented for Candida albicans than for other Candida species, therefore it was the aim of this study to investigate a) did cytochromes P450 exist in C. albicans that could possibly fulfil this function and b) to definitively assign function to a single cytochrome P450. Using a bioinformatic approach, five putative CYP52s were identified in C. albicans. Of these CYP52s, Alk1 was shown to have the greatest homology to the archetypal alkane-assimilating CYP52, CYP52A3 from C. maltosa. ALK1 heterologous gene expression in the brewer's yeast Saccharomyces cerevisiae allowed growth on hexadecane (C16:0) as the sole carbon source. This showed for the first time that Alk1 is involved in the hydroxylation of long-chain alkanes as normally S. cerevisiae is unable to utilise alkanes for growth. This study has also shown that Alk1 is able to interact with sterol substrates suggesting a possible role for CYP52s in sterol metabolism, which was previously unknown.
Keywords: Molecular biology.
College: Swansea University Medical School