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1n4n
From Proteopedia
| 1n4n, 20 NMR models () | |||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Contents |
Petunia hybrida Flowers Produce Two Unique Plant Defensins
The flowers of petunia (Petunia hybrida) accumulate high levels of at least two defensins (PhD1 and PhD2) as part of their defense armoury against potential pathogen infection. In contrast to the well-described seed defensins (Class I), these petunia floral defensins are produced as precursors with anionic C-terminal propeptides (CTPP) in addition to a typical secretion signal peptide and central basic defensin domain (47 amino acids) (Class II). PhD1 and PhD2 isolated from petunia flowers lack the CTPP, suggesting that it is removed during or after transit through the secretory pathway. In addition to the eight canonical cysteine residues that define the plant defensin family, PhD1 and PhD2 is unique to this family in that it contains an extra pair of cysteines that form a fifth disulfide bond. Hence, Lay et al. (2003) have defined them as a new subclass of this family of proteins.
Structure of the Plant Defensin PhD1 from Petunia hybrida
The structure of a novel plant defensin isolated from the flowers of Petunia hybrida has been determined by (1)H NMR spectroscopy. P. hybrida defensin 1 (PhD1) is a basic, cysteine-rich, antifungal protein of 47 residues and is the first example of a new subclass of plant defensins with five disulfide bonds whose structure has been determined. PhD1 has the fold of the cysteine-stabilized alphabeta motif, consisting of an alpha-helix and a triple-stranded antiparallel beta-sheet, except that it contains a fifth disulfide bond from the first loop to the alpha-helix. The additional disulfide bond is accommodated in PhD1 without any alteration of its tertiary structure with respect to other plant defensins. Comparison of its structure with those of classic, four-disulfide defensins has allowed us to identify a previously unrecognized hydrogen bond network that is integral to structure stabilization in the family.
Structure of Petunia hybrida defensin 1, a novel plant defensin with five disulfide bonds., Janssen BJ, Schirra HJ, Lay FT, Anderson MA, Craik DJ, Biochemistry. 2003 Jul 15;42(27):8214-22. PMID:12846570
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
1N4N is a Single protein structure of sequence from Petunia x hybrida. Full experimental information is available from OCA.
Reference
Structure of Petunia hybrida defensin 1, a novel plant defensin with five disulfide bonds., Janssen BJ, Schirra HJ, Lay FT, Anderson MA, Craik DJ, Biochemistry. 2003 Jul 15;42(27):8214-22. PMID:12846570
Page seeded by OCA on Sun Jul 27 15:58:39 2008
Related References
Defensins - Components of the innate immune system in plants., Lay FT, Anderson MA, Curr Protein Pept Sci. 2005 Feb;6(1):85-101. PMID:15638771 - review pointing out the salient features of Class I and Class II plant defensins
Isolation and properties of floral defensins from ornamental tobacco and petunia. Lay FT, Brugliera F, Anderson MA. Plant Physiol. 2003 Mar;131(3):1283-93. PMID:12644678 - original paper detailing the purification, expression and activity of PhD1 and PhD2
--Fung Lay 04:27, 1 August 2008 (IDT)
