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Characterization of L-ornithine-N5-oxygenase in A. fumigatus

Resource type
Thesis type
(Thesis) M.Sc.
Date created
2011-04-21
Authors/Contributors
Abstract
Aspergillus fumigatus is a major fungal pathogen of immunosuppressed patients. Recent studies demonstrated that hydroxamate-siderophore biosynthesis was required for virulence of A. fumigatus. SidA represents an excellent target for development of novel antifungal agents. In A. fumigatus the predominant hydroxamate-siderophore is N’, N’’, N’’’-triacetylfusarinine-C and its biosynthesis is initiated by hydroxylation of ornithine by ornithine-N5-oxygenase (SidA). The purpose of this research was to characterize SidA. AfSidA protein was cloned and expressed in an E. coli expression-vector. SidA was specific for its substrate L-ornithine, and cofactor FAD and preferred NADPH to NADH. L-lysine stimulated NADPH-oxidation but substrate hydroxylation was uncoupled. SidA had Michaelis-Menten kinetics and compared to bacterial ornithine-oxygenases, showed a higher thermotolerance and pH preference but a lower maximal velocity. A 3D-model of SidA was generated based on the crystal structure of phenylacetone-monooxygenase from Thermobifida fusca. Localization studies predicted a possible membrane association for SidA through its N-terminus.
Document
Identifier
etd6576
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The author granted permission for the file to be printed, but not for the text to be copied and pasted.
Scholarly level
Supervisor or Senior Supervisor
Thesis advisor: Moore, Margo M.
Member of collection
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etd6576_NGhavam.pdf 22.67 MB

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