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United States Department of Agriculture

Agricultural Research Service

Title: Pentaketide Melanin Biosynthesis in Aspergillus Fumigatus Requires Chain Length Shortening of a Heptaketide Precursor

Authors
item Tsai, Huei-Fung - NIAID
item Fujii, Isao - UNIVERSITY OF TOKYO
item Watanabe, Akira - UNIVERSITY OF TOKYO
item Wheeler, Michael
item Chang, Yun - NIAID
item Ebizuka, Yutaka - UNIVERSITY OF TOKYO
item Kwon-Chung, K. - NIAID

Submitted to: Journal of Biological Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2000
Publication Date: N/A

Interpretive Summary: Molds (also called fungi) occur widely in nature and some are associated with important crops such as cotton. Certain molds produce chemicals (called polyketides) that may be colored pigments, toxins, or that even have antibiotic activity and are used as human and animal drugs. This research used sophisticated methods of biochemistry and molecular biology to show that in the fungus known as Aspergillus fumigatus, certain interactions between polyketides and another mold chemical (a unique protein) result in the polyketides being changed in such a manner that production of a dark pigment (melanin) by the fungus is affected. This research is important because Aspergillus fumigatus and related fungi are harmful to plants or animals and a better understanding of how the fungi work can help in developing effective methods for its control. Document1 Last printed XXX 0, 0000 0:00 AM

Technical Abstract: Polyketides are a type of compound produced in nature that include fungal pigments, toxins, antibiotics, and a number of known pharmaceutical drugs. Pentaketide melanins, a type of polyketides pigment, are known to help various plant and human pathogenic fungi infect their host organisms. In this study, we used genetic and biochemical methods and found that a unique protein produced by the bluish-green colored pathogen, Aspergillus fumigatus, shortened the length of a polyketides molecule used in melanin synthesis by four carbon units. The significance of this finding is that the unique protein, designated as Ayg1p, facilitates the participation of larger compounds in A. fumigatus to produce smaller precursor compounds (building blocks) required for melanin synthesis. This protein is not produced by brown to black fungi that make melanins related to that in A. fumigatus and it appears that these fungi produce the same melanin building blocks by a similar but different pathway.

Last Modified: 8/27/2014
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