固态 NMR 和分子动力学模拟揭示了仿生细菌膜中牛乳铁蛋白肽的结构和取向。
Structure and orientation of bovine lactoferrampin in the mimetic bacterial membrane as revealed by solid-state NMR and molecular dynamics simulation.
机构信息
Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa, Japan.
出版信息
Biophys J. 2012 Oct 17;103(8):1735-43. doi: 10.1016/j.bpj.2012.09.010. Epub 2012 Oct 16.
Bovine lactoferrampin (LFampinB) is a newly discovered antimicrobial peptide found in the N1-domain of bovine lactoferrin (268-284), and consists of 17 amino-acid residues. It is important to determine the orientation and structure of LFampinB in bacterial membranes to reveal the antimicrobial mechanism. We therefore performed (13)C and (31)P NMR, (13)C-(31)P rotational echo double resonance (REDOR), potassium ion-selective electrode, and quartz-crystal microbalance measurements for LFampinB with mimetic bacterial membrane and molecular-dynamics simulation in acidic membrane. (31)P NMR results indicated that LFampinB caused a defect in mimetic bacterial membranes. Ion-selective electrode measurements showed that ion leakage occurred for the mimetic bacterial membrane containing cardiolipin. Quartz-crystal microbalance measurements revealed that LFampinB had greater affinity to acidic phospholipids than that to neutral phospholipids. (13)C DD-MAS and static NMR spectra showed that LFampinB formed an α-helix in the N-terminus region and tilted 45° to the bilayer normal. REDOR dephasing patterns between carbonyl carbon nucleus in LFampinB and phosphorus nuclei in lipid phosphate groups were measured by (13)C-(31)P REDOR and the results revealed that LFampinB is located in the interfacial region of the membrane. Molecular-dynamics simulation showed the tilt angle to be 42° and the rotation angle to be 92.5° for Leu(3), which are in excellent agreement with the experimental values.
牛乳铁传递蛋白抗菌肽（LFampinB）是一种新发现的抗菌肽，存在于牛乳铁蛋白的 N1 结构域（268-284）中，由 17 个氨基酸残基组成。确定 LFampinB 在细菌膜中的取向和结构对于揭示其抗菌机制非常重要。因此，我们在模拟细菌膜中进行了（13）C 和（31）P NMR、（13）C-（31）P 旋转回波双共振（REDOR）、钾离子选择性电极和石英晶体微天平测量，以及酸性膜中的分子动力学模拟。（31）P NMR 结果表明 LFampinB 导致模拟细菌膜出现缺陷。离子选择性电极测量表明，含有心磷脂的模拟细菌膜发生离子泄漏。石英晶体微天平测量表明，LFampinB 对酸性磷脂的亲和力大于中性磷脂。（13）C DD-MAS 和静态 NMR 谱表明，LFampinB 在 N 端区域形成α-螺旋，与双层膜法线成 45°倾斜。通过（13）C-（31）P REDOR 测量 LFampinB 中羰基碳原子核与脂质磷酸盐基团中磷原子核之间的 REDOR 去相位模式，结果表明 LFampinB 位于膜的界面区域。分子动力学模拟表明 Leu（3）的倾斜角为 42°，旋转角为 92.5°，与实验值非常吻合。
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