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Cyclotide proteins and precursors from the genus Gloeospermum: filling a blank spot in the cyclotide map of Violaceae.
- Source :
-
Phytochemistry [Phytochemistry] 2010 Jan; Vol. 71 (1), pp. 13-20. Date of Electronic Publication: 2009 Oct 30. - Publication Year :
- 2010
-
Abstract
- Cyclotides are disulfide-rich plant proteins that are exceptional in their cyclic structure; their N and C termini are joined by a peptide bond, forming a continuous circular backbone, which is reinforced by three interlocked disulfide bonds. Cyclotides have been found mainly in the coffee (Rubiaceae) and violet (Violaceae) plant families. Within the Violaceae, cyclotides seem to be widely distributed, but the cyclotide complements of the vast majority of Violaceae species have not yet been explored. This study provides insight into cyclotide occurrence, diversity and biosynthesis in the Violaceae, by identifying mature cyclotide proteins, their precursors and enzymes putatively involved in their biosynthesis in the tribe Rinoreeae and the genus Gloeospermum. Twelve cyclotides from two Panamanian species, Gloeospermum pauciflorum Hekking and Gloeospermum blakeanum (Standl.) Hekking (designated Glopa A-E and Globa A-G, respectively) were characterised through cDNA screening and protein isolation. Screening of cDNA for the oxidative folding enzymes protein-disulfide isomerase (PDI) and thioredoxin (TRX) resulted in positive hits in both species. These enzymes have demonstrated roles in oxidative folding of cyclotides in Rubiaceae, and results presented here indicate that Violaceae plants have evolved similar mechanisms of cyclotide biosynthesis. We also describe PDI and TRX sequences from a third cyclotide-expressing Violaceae species, Viola biflora L., which further support this hypothesis.<br /> (2009 Elsevier Ltd. All rights reserved.)
- Subjects :
- Amino Acid Sequence
Cyclotides chemistry
Cyclotides isolation & purification
DNA, Complementary
Molecular Sequence Data
Panama
Plant Leaves
Plant Proteins genetics
Protein Disulfide-Isomerases genetics
Protein Folding
Thioredoxins genetics
Violaceae genetics
Cyclotides biosynthesis
Genes, Plant
Plant Proteins metabolism
Protein Disulfide-Isomerases metabolism
Thioredoxins metabolism
Violaceae metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1873-3700
- Volume :
- 71
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Phytochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19879608
- Full Text :
- https://doi.org/10.1016/j.phytochem.2009.09.023