A non-canonical melanin biosynthesis pathway protects Aspergillus terreus conidia from environmental stress

Geib, Elena and Gressler, Markus and Viediernikova, Iuliia and Hillmann, Falk and Jacobsen, Ilse D. and Nietzsche, Sandor and Hertweck, Christian and Brock, Matthias (2016) A non-canonical melanin biosynthesis pathway protects Aspergillus terreus conidia from environmental stress. Cell Chemical Biology, 23 (5). pp. 587-597. ISSN 2451-9456

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Abstract

Pro- and eukaryotes produce melanin for protection from environmental stress or as virulence determinant. The human pathogenic fungus Aspergillus fumigatus and related Ascomycetes produce dihydroxynaphthalene (DHN) melanin in conidia, which is essential for inhibiting phagolysosome acidification. In contrast, Aspergillus terreus lacks genes for biosynthesis of DHN-melanin. Therefore, the origin of the pigment in A. terreus conidia was elucidated. Expression analyses from conidiation conditions identified genes coding for an unusual NRPS-like enzyme (MelA) and a tyrosinase. MelA produces aspulvinone E as precursor, which is activated for polymerisation by the tyrosinase TyrP as shown by heterologous in vivo and in vitro reconstitution of pigment formation. Functional studies revealed that the pigment confers resistance against UV-light and hampers phagocytosis by soil amoeba, but does not inhibit acidification of phagolysosomes. Since A. terreus conidia prefer persistence at acidic pH, this uncommon type of melanin, termed Asp-melanin, might specifically contribute to survival in the environment.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Life Sciences
Identification Number: https://doi.org/10.1016/j.chembiol.2016.03.014
Depositing User: Eprints, Support
Date Deposited: 21 May 2016 17:29
Last Modified: 17 Sep 2016 20:01
URI: http://eprints.nottingham.ac.uk/id/eprint/33069

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