| 1. |
- Plan, Manuel Rey R, et al.
(författare)
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The cyclotide fingerprint in Oldenlandia affinis : elucidation of chemically modified, linear and novel macrocyclic peptides
- 2007
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 8:9, s. 1001-1011
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Tidskriftsartikel (refereegranskat)abstract
- The complete suite of cyclotides present in Oldenlandia affinis (Rubiaceae), the plant that was originally found to contain this unique family of circular proteins, has been characterised. This study expands the number of known cyclotides in this plant to 17, of which nine new sequences (kalata B9-B17) were characterised in this work. In addition, five derivatives that contain oxidation products of the conserved tryptophan were identified, and it was shown that the formation of these derivatives is catalysed by exposure to sunlight. Furthermore, we describe two linear cyclotide analogues. These acyclic peptides have three intact disulfide bonds, and their N and C termini coincide with the hypothesised cleavage sites from the precursor protein. This work increases our knowledge about the sequence variation that is accommodated by the cyclic cystine knot scaffold, confirms its applicability as a template for drug design, and also shows the first natural degradation pathways for cyclotides. These pathways have important implications for the persistence and environmental fate of the cyclotides if used as crop-protection agents.
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| 2. |
- Wang, Conan K L, et al.
(författare)
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Anti-HIV cyclotides from the Chinese medicinal herb Viola yedoensis
- 2008
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Ingår i: Journal of natural products (Print). - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 71:1, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- Cyclotides are macrocyclic plant peptides characterized by a knotted arrangement of three disulfide bonds. They display a range of interesting bioactivities, including anti-HIV and insecticidal activities. More than 100 different cyclotides have been isolated from two phylogenetically distant plant families, the Rubiaceae and Violaceae. In this study we have characterized the cyclotides from Viola yedoensis, an important Chinese herb from the Violaceae family that has been reported to contain potential anti-HIV agents. From V. yedoensis five new and three known cyclotides were identified and shown to have anti-HIV activity. The most active of these is cycloviolacin Y5, which is one of the most potent of all cyclotides tested so far using in vitro XTT-based anti-HIV assays. Cycloviolacin Y5 is the most hydrophobic of the cyclotides from V. yedoensis. We show that there is a positive correlation between the hydrophobicity and the anti-HIV activity of the new cyclotides and that this trend tracks with their ability to disrupt membranes, as judged from hemolytic assays on human erythrocytes.
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| 3. |
- Colgrave, Michelle L., et al.
(författare)
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Neuropeptide profiling of the bovine hypothalamus : Thermal stabilization is an effective tool in inhibiting post-mortem degradation
- 2011
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Ingår i: Proteomics. - : Wiley. - 1615-9853 .- 1615-9861. ; 11:7, s. 1264-1276
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Tidskriftsartikel (refereegranskat)abstract
- The hypothalamus is the central regulatory region of the brain that links the nervous system to the endocrine system via the pituitary gland. It synthesizes and secretes neuropeptide hormones, which in turn act to stimulate or inhibit the secretion of pituitary hormones. We have undertaken a detailed MS investigation of the peptides present in the bovine hypothalamus by adapting a novel heat stabilization methodology, which improved peptide discovery to direct our studies into the molecular mechanisms involved in bovine reproduction. The untreated samples contained large numbers of protein degradation products that interfered with the analysis of the neuropeptides. In the thermally stabilized samples, we were able to identify many more neuropeptides that are known to be expressed in the bovine hypothalamus. Furthermore, we have characterized a range of post-translational modifications that indicate the presence of processed intact mature neuropeptides in the stabilized tissue samples, whereas we detected many trimmed or truncated peptides resulting from post-mortem degradation in the untreated tissue samples. Altogether, using an optimized workflow, we were able to identify 140 candidate neuropeptides. We also nominate six new candidate neuropeptides derived from proSAAS, secretogranin-2 and proTRH.
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| 4. |
- Kamal, Nadia, et al.
(författare)
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The mosaic oat genome gives insights into a uniquely healthy cereal crop
- 2022
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 606:7912, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- Cultivated oat (Avena sativa L.) is an allohexaploid (AACCDD, 2n = 6x = 42) thought to have been domesticated more than 3,000 years ago while growing as a weed in wheat, emmer and barley fields in Anatolia1,2. Oat has a low carbon footprint, substantial health benefits and the potential to replace animal-based food products. However, the lack of a fully annotated reference genome has hampered efforts to deconvolute its complex evolutionary history and functional gene dynamics. Here we present a high-quality reference genome of A. sativa and close relatives of its diploid (Avena longiglumis, AA, 2n = 14) and tetraploid (Avena insularis, CCDD, 2n = 4x = 28) progenitors. We reveal the mosaic structure of the oat genome, trace large-scale genomic reorganizations in the polyploidization history of oat and illustrate a breeding barrier associated with the genome architecture of oat. We showcase detailed analyses of gene families implicated in human health and nutrition, which adds to the evidence supporting oat safety in gluten-free diets, and we perform mapping-by-sequencing of an agronomic trait related to water-use efficiency. This resource for the Avena genus will help to leverage knowledge from other cereal genomes, improve understanding of basic oat biology and accelerate genomics-assisted breeding and reanalysis of quantitative trait studies.
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| 5. |
- Simonsen, Shane M, et al.
(författare)
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A continent of plant defense peptide diversity : cyclotides in Australian Hybanthus (Violaceae)
- 2005
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Ingår i: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 17:11, s. 3176-3189
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Tidskriftsartikel (refereegranskat)abstract
- Cyclotides are plant-derived miniproteins that have the unusual features of a head-to-tail cyclized peptide backbone and a knotted arrangement of disulfide bonds. It had been postulated that they might be an especially large family of host defense agents, but this had not yet been tested by field data on cyclotide variation in wild plant populations. In this study, we sampled Australian Hybanthus (Violaceae) to gain an insight into the level of variation within populations, within species, and between species. A wealth of cyclotide diversity was discovered: at least 246 new cyclotides are present in the 11 species sampled, and 26 novel sequences were characterized. A new approach to the discovery of cyclotide sequences was developed based on the identification of a conserved sequence within a signal sequence in cyclotide precursors. The number of cyclotides in the Violaceae is now estimated to be >9000. Cyclotide physicochemical profiles were shown to be a useful taxonomic feature that reflected species and their morphological relationships. The novel sequences provided substantial insight into the tolerance of the cystine knot framework in cyclotides to amino acid substitutions and will facilitate protein engineering applications of this framework.
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| 6. |
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