Plant lipocalins: violaxanthin de-epoxidase and zeaxanthin epoxidase

Hieber, A. David; Bugos, Robert C.; Yamamoto, Harry Y.

doi:10.1016/s0167-4838(00)00141-2

Cited by 155 publications

(134 citation statements)

References 50 publications

Supporting

Mentioning

130

Contrasting

Unclassified

Order By: Relevance

“…The Arabidopsis mutants defective in the single VDE/ NPQ1 (At1g08550) and ZEP/NPQ2/ABA1 (At5g67030) genes were key to define the role of this cycle in photoprotection Niyogi, 1999). The xanthophyll cycle is uniquely separated on opposite sides of the thylakoid membrane ( Figure 6): VDE activity takes place on the thylakoid lumen side of the membrane, whereas ZEP occurs on the chloroplast stromal side (Demmig-Adams et al, 1996;Hieber et al, 2000;Yamamoto, 2006). Consistent with the described distribution, proteomic approaches have identified the Arabidopsis VDE enzyme only in thylakoids, whereas ZEP was localized in both envelope and thylakoid membranes (Joyard et al, 2009) (Table 1).…”

Section: Xanthophyll Cycle Enzymesmentioning

confidence: 99%

“…Plant VDE is usually encoded by single genes, whereas small gene families encode ZEP in some plants, including maize (www.phytozome.net) ). Both enzymes have characteristic conserved domains, including a lipocalin signature shared by other proteins that are able to bind hydrophobic molecules such as the apocarotenoid retinal (Hieber et al, 2000).…”

Section: Xanthophyll Cycle Enzymesmentioning

confidence: 99%

See 1 more Smart Citation

Carotenoid Biosynthesis in Arabidopsis: A Colorful Pathway

Ruiz-Sola

Rodríguez‐Concepción

2012

The Arabidopsis Book

475

372

View full text Add to dashboard Cite

Plant carotenoids are a family of pigments that participate in light harvesting and are essential for photoprotection against excess light. Furthermore, they act as precursors for the production of apocarotenoid hormones such as abscisic acid and strigolactones. In this review, we summarize the current knowledge on the genes and enzymes of the carotenoid biosynthetic pathway (which is now almost completely elucidated) and on the regulation of carotenoid biosynthesis at both transcriptional and post-transcriptional levels. We also discuss the relevance of Arabidopsis as a model system for the study of carotenogenesis and how metabolic engineering approaches in this plant have taught important lessons for carotenoid biotechnology.

show abstract

Section: Xanthophyll Cycle Enzymesmentioning

confidence: 99%

Section: Xanthophyll Cycle Enzymesmentioning

confidence: 99%

Carotenoid Biosynthesis in Arabidopsis: A Colorful Pathway

Ruiz-Sola

Rodríguez‐Concepción

2012

The Arabidopsis Book

475

372

View full text Add to dashboard Cite

show abstract

“…Oxidation of the terminal double bonds is characteristic for other enzymatic reactions (Lucas et al , 2010 ). Zeaxanthin epoxidase oxidizes double bonds only at the ends of zeaxantin, despite the fact that this substrate, like squalene, contains several internal double bonds which could be potentially epoxidized (Hieber et al , 2000 ).…”

Section: Specifi City Of Epoxidation Reactionmentioning

confidence: 99%

Squalene monooxygenase – a target for hypercholesterolemic therapy

Belter¹,

Skupińska²,

Giel-Pietraszuk

et al. 2011

BCHM

View full text Add to dashboard Cite

Squalene monooxygenase catalyzes the epoxidation of C-C double bond of squalene to yield 2,3-oxidosqualene, the key step of sterol biosynthesis pathways in eukaryotes. Sterols are essential compounds of these organisms and squalene epoxidation is an important regulatory point in their synthesis. Squalene monooxygenase downregulation in vertebrates and fungi decreases synthesis of cholesterol and ergosterol, respectively, which makes squalene monooxygenase a potent and attractive target of hypercholesterolemia and antifungal therapies. Currently some fungal squalene monooxygenase inhibitors (terbinafi ne, naftifi ne, butenafi ne) are in clinical use, whereas mammalian enzymes ' inhibitors are still under investigation. Research on new squalene monooxygenase inhibitors is important due to the prevalence of hypercholesterolemia and the lack of both suffi cient and safe remedies. In this paper we (i) review data on activity and the structure of squalene monooxygenase, (ii) present its inhibitors, (iii) compare current strategies of lowering cholesterol level in blood with some of the most promising strategies, (iv) underline advantages of squalene monooxygenase as a target for hypercholesterolemia therapy, and (v) discuss safety concerns about hypercholesterolemia therapy based on inhibition of cellular cholesterol biosynthesis and potential usage of squalene monooxygenase inhibitors in clinical practice. After many years of use of statins there is some clinical evidence for their adverse effects and only partial effectiveness. Currently they are drugs of choice but are used with many restrictions, especially in case of children, elderly patients and women of childbearing potential. Certainly, for the next few years, statins will continue to be a suitable tool for cost-effective cardiovascular prevention; however research on new hypolipidemic drugs is highly desirable. We suggest that squalene monooxygenase inhibitors could become the hypocholesterolemic agents of the future.

show abstract

“…Ferricyanide reduction α 1 m, 5-40 µM in 20 mM Tris-HCl, pH 7.4, 150 mM NaCl, was incubated with 500 µM potassium ferricyanide (K 3 Fe(CN) 6 ) at room temperature for 90 minutes. The amounts of produced ferrocyanide were determined using bathophenanthrolinedisulfonic acid (SigmaChemicals) as described by Avron and Shavit [27] by measuring the increase of absorbance at 535 nm and using the reagents as a blank.…”

Section: Methemoglobin Reductionmentioning

confidence: 99%

“…The interior of the barrel forms a binding site for small hydrophobic ligands and this structural property is the basis for a surprisingly wide array of biological functions. Retinol-binding protein and prostaglandin D-synthase from mammals, insect bilin-binding protein and plant violaxanthinde-epoxygenase are examples of lipocalins [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Redox properties of the lipocalin α1-microglobulin: Reduction of cytochrome c, hemoglobin, and free iron

Maria

Klapyta

Åkerström

2005

Free Radical Biology and Medicine

View full text Add to dashboard Cite

Abstractα 1 -microglobulin (α 1 m) is a 26 kDa plasma and tissue glycoprotein. The protein has a heterogeneous yellow-brown chromophore consisting of small unidentified prosthetic groups localized to a free thiol group (C34) and three lysyl residues (K92, K118 and K130) around the entrance to a hydrophobic pocket. It was recently reported that α 1 m can bind heme and that a C-terminally processed form of α 1 m degrades heme. It is shown here that α 1 m has catalytic reductase and NADH-dehydrogenase-like activities. Cytochrome c, nitroblue tetrazolium (NBT), methemoglobin and ferricyanide were reduced by α 1 m. Comparison of the reduction rates suggests that methemoglobin is a better substrate than cytochrome c, NBT and ferricyanide. The reactions with cytochrome c and NBT were mediated by superoxide anions since they were inhibited by superoxide dismutase. The addition of the biological electron donors NADH, NADPH or ascorbate enhanced the reduction rate of cytochrome c approximately 30-fold. Recombinant α 1 m, which has much less chromophore than plasma and urine α 1 m, was a stronger reductant than the latter α 1 m-forms. Site-directed mutagenesis of C34, K92, K118 and K130 and thiol group chemistry showed that the C34 thiol group was involved in the redox reaction but relies upon co-operation with the lysyl residues. The redox properties of α 1 m may provide a physiological protection mechanism against extracellularly exposed heme-groups and other oxidants.

show abstract

Plant lipocalins: violaxanthin de-epoxidase and zeaxanthin epoxidase

Cited by 155 publications

References 50 publications

Carotenoid Biosynthesis in Arabidopsis: A Colorful Pathway

Carotenoid Biosynthesis in Arabidopsis: A Colorful Pathway

Squalene monooxygenase – a target for hypercholesterolemic therapy

Redox properties of the lipocalin α1-microglobulin: Reduction of cytochrome c, hemoglobin, and free iron

Contact Info

Product

Resources

About