Novel apocarotenoid intermediates in Neurospora crassa mutants imply a new biosynthetic reaction sequence leading to neurosporaxanthin formation

Estrada, Alejandro F.; Maier, Dominic; Scherzinger, Daniel; Ávalos, Javier; Al‐Babili, Salim

doi:10.1016/j.fgb.2008.09.001

Cited by 36 publications

(39 citation statements)

References 46 publications

(60 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6). Their availability depends on the growth conditions: ␤-apo-4=-carotenal (C 35 ) is preferentially used by Neurospora as an intermediate of the pathway under illumination at 30°C, and apo-4=-lycopenal is preferentially used under illumination at cold temperature (56). Because of its similarity to retinal and its formation at a physiological temperature, ␤-apo-4=-carotenal is a more-plausible candidate.…”

Section: Discussionmentioning

confidence: 99%

The Oxygenase CAO-1 of Neurospora crassa Is a Resveratrol Cleavage Enzyme

et al. 2013

Self Cite

View full text Add to dashboard Cite

bThe genome of the ascomycete Neurospora crassa encodes CAO-1 and CAO-2, two members of the carotenoid cleavage oxygenase family that target double bonds in different substrates. Previous studies demonstrated the role of CAO-2 in cleaving the C 40 carotene torulene, a key step in the synthesis of the C 35 apocarotenoid pigment neurosporaxanthin. In this work, we investigated the activity of CAO-1, assuming that it may provide retinal, the chromophore of the NOP-1 rhodopsin, by cleaving ␤-carotene.For this purpose, we tested CAO-1 activity with carotenoid substrates that were, however, not converted. In contrast and consistent with its sequence similarity to family members that act on stilbenes, CAO-1 cleaved the interphenyl C␣-C␤ double bond of resveratrol and its derivative piceatannol. CAO-1 did not convert five other similar stilbenes, indicating a requirement for a minimal number of unmodified hydroxyl groups in the stilbene background. Confirming its biological function in converting stilbenes, adding resveratrol led to a pronounced increase in cao-1 mRNA levels, while light, a key regulator of carotenoid metabolism, did not alter them. Targeted ⌬cao-1 mutants were not impaired by the presence of resveratrol, a phytoalexin active against different fungi, which did not significantly affect the growth and development of wild-type Neurospora. However, under partial sorbose toxicity, the ⌬cao-1 colonies exhibited faster radial growth than control strains in the presence of resveratrol, suggesting a moderate toxic effect of resveratrol cleavage products.

show abstract

Section: Discussionmentioning

confidence: 99%

The Oxygenase CAO-1 of Neurospora crassa Is a Resveratrol Cleavage Enzyme

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…A f-carotene-accumulating strain was generated by transforming TOP 10 E. coli cells with pZeta, a pPhytoene (Estrada et al 2008) derivative equipped with phytoene desaturase from Synechocystis sp. PCC 6803.…”

Section: Expression In Carotenoid-accumulating E Coli Strainsmentioning

confidence: 99%

On the substrate specificity of the rice strigolactone biosynthesis enzyme DWARF27

Bruno

Al‐Babili

2016

Planta

Self Cite

View full text Add to dashboard Cite

The β-carotene isomerase OsDWARF27 is stereo- and double bond-specific. It converts bicyclic carotenoids with at least one unsubstituted β-ionone ring. OsDWARF27 may contribute to the formation of α-carotene-based strigolactone-like compounds. Strigolactones (SLs) are synthesized from all-trans-β-carotene via a pathway involving the β-carotene isomerase DWARF27, the carotenoid cleavage dioxygenases 7 and 8 (CCD7, CCD8), and cytochrome P450 enzymes from the 711 clade (MAX1 in Arabidopsis). The rice enzyme DWARF27 was shown to catalyze the reversible isomerization of all-trans- into 9-cis-β-carotene in vitro. β-carotene occurs in different cis-isomeric forms, and plants accumulate other carotenoids, which may be substrates of DWARF27. Here, we investigated the stereo and substrate specificity of the rice enzyme DWARF27 in carotenoid-accumulating E. coli strains and in in vitro assays performed with heterologously expressed and purified enzyme. Our results suggest that OsDWARF27 is strictly double bond-specific, solely targeting the C9-C10 double bond. OsDWARF27 did not introduce a 9-cis-double bond in 13-cis- or 15-cis-β-carotene. Substrates isomerized by OsDWARF27 are bicyclic carotenoids, including β-, α-carotene and β,β-cryptoxanthin, that contain at least one unsubstituted β-ionone ring. Accordingly, OsDWARF27 did not produce the abscisic acid precursors 9-cis-violaxanthin or -neoxanthin from the corresponding all-trans-isomers, excluding a direct role in the formation of this carotenoid derived hormone. The conversion of all-trans-α-carotene yielded two different isomers, including 9'-cis-α-carotene that might be the precursor of strigolactones with an ε-ionone ring, such as the recently identified heliolactone.

show abstract

“…Neurosporaxanthin is produced from torulene through an oxidative cleavage reaction and a final oxidation of the resulting aldehyde group. This biosynthetic pathway is very similar in N. crassa, although the order of the reactions may differ (Estrada et al, 2008a). As a side branch from this pathway, the precursor c-carotene may be also cycled to produce b-carotene, which in turn is converted to retinal through a central cleavage reaction.…”

Section: Photocarotenogenesismentioning

confidence: 99%