Structure of Petunia hybrida defensin 1, a novel plant defensin with five disulfide bonds.
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.
Janssen
Bert J C
BJ
Institute for Molecular Bioscience, ARC Special Research Center for Functional and Applied Genomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
Schirra
Horst Joachim
HJ
Lay
Fung T
FT
Anderson
Marilyn A
MA
Craik
David J
DJ
D000595:Amino Acid Sequence; D023082:Defensins / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D032306:Petunia / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D055672:Static Electricity
D023082:Defensins; D004220:Disulfides