Solution structure of a defensin-like peptide from platypus venom.
Three defensin-like peptides (DLPs) were isolated from platypus venom and sequenced. One of these peptides, DLP-1, was synthesized chemically and its three-dimensional structure was determined using NMR spectroscopy. The main structural elements of this 42-residue peptide were an anti-parallel beta-sheet comprising residues 15-18 and 37-40 and a small 3(10) helix spanning residues 10-12. The overall three-dimensional fold is similar to that of beta-defensin-12, and similar to the sodium-channel neurotoxin ShI (Stichodactyla helianthus neurotoxin I). However, the side chains known to be functionally important in beta-defensin-12 and ShI are not conserved in DLP-1, suggesting that it has a different biological function. Consistent with this contention, we showed that DLP-1 possesses no anti-microbial properties and has no observable activity on rat dorsal-root-ganglion sodium-channel currents.
Department of Biochemistry, University of Sydney, NSW 2006, Australia.
A M
AM
Torres
X
X
Wang
J I
JI
Fletcher
D
D
Alewood
P F
PF
Alewood
R
R
Smith
R J
RJ
Simpson
G M
GM
Nicholson
S K
SK
Sutherland
C H
CH
Gallagher
G F
GF
King
P W
PW
Kuchel
D000595:Amino Acid Sequence; D000818:Animals; D023082:Defensins; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010987:Platypus; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012996:Solutions; D014649:Vas Deferens / Q000187:drug effects; D014688:Venoms / Q000737:chemistry* / Q000633:toxicity
D023082:Defensins; D011506:Proteins; D012996:Solutions; D014688:Venoms; C121145:defensin-like peptide 1, platypus