Melanization of flavonoids by fungal and bacterial laccases.
Yeast
; 28(3): 181-8, 2011 Mar.
Article
em En
| MEDLINE
| ID: mdl-21360730
ABSTRACT
Laccase activity in plants results in the formation of a number of brown pigments, often referred to as tannins. Laccase-dependent pigment production is also catalogued in numerous fungal and bacterial species. The laccase of the haploid yeast Cryptococcus neoformans forms melanin-like pigmentation outside the cell wall in the presence of exogenous substrates. While this process is a contributing factor to its virulence in humans, the evolutionary intent for the laccase function remains a mystery. We show here that C. neoformans and Bacillus subtilis have the ability to create melanin-like pigments from a variety of flavonoid molecules across a range of conformations, preferring those with 3',4'-dihydroxylations. Since flavonoids are ubiquitous plant molecules and often-considered antimicrobial agents, we postulate that they are the intended natural targets of laccase activity and result in the formation of a defensive melanin-like coat. These results suggests a new mechanism by which flavonoid-melanin formation may occur, using not only A- and C-ring linkages, but also monomer links through the B-ring of the flavonoid structure. We also show that resveratrol and other non- and mono-hydroxylated polyphenol substrates have the ability to restrict pigment formation and may be potent inhibitors of laccase activity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bacillus subtilis
/
Flavonoides
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Cryptococcus neoformans
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Lacase
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Melaninas
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article