Document Detail


Novel apocarotenoid intermediates in Neurospora crassa mutants imply a new biosynthetic reaction sequence leading to neurosporaxanthin formation.
MedLine Citation:
PMID:  18812228     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Neurosporaxanthin, beta-apo-4'-carotenoic acid (C35), represents the end-product of the carotenoid pathway in Neurospora crassa. It is supposed to be synthesized in three steps catalyzed by sequential AL-2, CAO-2 and YLO-1 activities: (i) cyclization of 3,4-didehydrolycopene (C40); (ii) cleavage of torulene into beta-apo-4'-carotenal (C35); and finally (iii) oxidation of beta-apo-4'-carotenal. However, analyses of the ylo-1 mutant revealed the accumulation of intermediates other than beta-apo-4'-carotenal. Here, we generated a 3,4-didehydrolycopene accumulating Escherichia coli strain and showed that CAO-2 cleaves this acyclic carotene in vivo and in vitro yielding apo-4'-lycopenal. The apocarotenoids accumulated in the ylo-1 mutant were then identified as apo-4'-lycopenal and apo-4'-lycopenol, pointing to the former as the YLO-1 substrate and indicating that cyclization is the last step in neurosporaxanthin biosynthesis. This was further substantiated by analyses of a cyclase-deficient al-2 mutant, revealing the accumulation of apo-4'-lycopenoic acid. The three acyclic apocarotenoids presented here have not been found naturally before.
Authors:
Alejandro F Estrada; Dominic Maier; Daniel Scherzinger; Javier Avalos; Salim Al-Babili
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-09-10
Journal Detail:
Title:  Fungal genetics and biology : FG & B     Volume:  45     ISSN:  1096-0937     ISO Abbreviation:  Fungal Genet. Biol.     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2008-11-10     Completed Date:  2008-11-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9607601     Medline TA:  Fungal Genet Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1497-505     Citation Subset:  IM    
Affiliation:
Department of Genetics, Faculty of Biology, University of Seville, E-41012 Seville, Spain.
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MeSH Terms
Descriptor/Qualifier:
Biosynthetic Pathways*
Carotenoids / biosynthesis*,  genetics
Fungal Proteins / genetics,  metabolism
Gene Expression Regulation, Fungal
Lactones / metabolism
Mutation*
Neurospora crassa / enzymology,  genetics*,  metabolism*
Chemical
Reg. No./Substance:
0/Fungal Proteins; 0/Lactones; 0/lycoperdic acid; 0/neurosporaxanthin; 36-88-4/Carotenoids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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