Torres A M, Wang X, Fletcher J I, Alewood D, Alewood P F, Smith R, Simpson R J, Nicholson G M, Sutherland S K, Gallagher C H, King G F, Kuchel P W
Department of Biochemistry, University of Sydney, NSW 2006, Australia.
Biochem J. 1999 Aug 1;341 ( Pt 3)(Pt 3):785-94.
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.
从鸭嘴兽毒液中分离出三种防御素样肽（DLP）并进行了测序。其中一种肽，即DLP-1，通过化学合成得到，其三维结构利用核磁共振光谱法确定。这种由42个氨基酸残基组成的肽的主要结构元件是由15-18位和37-40位残基组成的反平行β-折叠以及跨越10-12位残基的一个小的3(10)螺旋。其整体三维折叠结构与β-防御素-12相似，也与钠通道神经毒素ShI（日光海葵神经毒素I）相似。然而，已知在β-防御素-12和ShI中具有功能重要性的侧链在DLP-1中并不保守，这表明它具有不同的生物学功能。与此观点一致的是，我们发现DLP-1不具有抗菌特性，并且对大鼠背根神经节钠通道电流没有可观察到的活性。
