The solution structures of the human β-defensins lead to a better understanding of the potent bactericidal activity of HBD3 against Staphylococcus aureus
The solution structures of the human β-defensins lead to a better understanding of the potent bactericidal activity of HBD3 against Staphylococcus aureus
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DOI：
10.1074/jbc.m108830200
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发表时间：
2002-03-08
影响因子：
4.8
通讯作者：
Vogel, HJ
中科院分区：
文献类型：
--
作者：
Schibli, DJ;Hunter, HN;Vogel, HJ
三种人β -防御素HBD1-3是由上皮细胞表达的33-47残基阳离子抗菌蛋白。这三种蛋白都具有广谱抗菌活性，其中HBD3一直是最有效的。此外，在生理盐浓度下，HBD3对革兰氏阳性金黄色葡萄球菌具有显著的杀菌活性。我们利用核磁共振扩散光谱、动态和静态光散射以及三种β -防御素在天然凝胶上的迁移分析，比较了三种β -防御素的多聚态。这三种技术都是一致的，表明HBD-3是二聚体，而HBD-1和HBD-2是单体。随后，使用标准同型核技术确定HBD1和HBD3的核磁共振溶液结构，并与先前确定的HBD2溶液结构进行比较。HBD1和HBD3结构清晰，主均方根偏差分别为0.451和0.616埃。所有三种β -防御素的三级结构是相似的，在三股反平行β -片之前有一个短的螺旋段。每种防御素的表面电荷密度有明显差异，HBD3表面的碱性明显更强。对核磁共振数据和结构的分析使我们认为HBD3通过β片的β 2链形成对称的二聚体。HBD3抗葡萄球菌活性的增强可能是由于该蛋白在低浓度溶液中形成二聚体的能力、两亲二聚体结构以及与HBD1和HBD2相比表面正电荷的增加。
The three human beta-defensins, HBD1-3, are 33-47-residue, cationic antimicrobial proteins expressed by epithelial cells. All three proteins have broad spectrum antimicrobial activity, with HBD3 consistently being the most potent. Additionally, HBD3 has significant bactericidal activity against Gram-positive Staphylococcus aureus at physiological salt concentrations. We have compared the multimeric state of the three beta-defensins using NMR diffusion spectroscopy, dynamic and static light scattering, and analysis of the migration of the three beta-defensins on a native gel. All three techniques are in agreement, suggesting that HBD-3 is a dimer, while HBD-1 and HBD-2 are monomeric. Subsequently, the NMR solution structures of HBD1 and HBD3 were determined using standard homonuclear techniques and compared with the previously determined solution structure of HBD2. Both HBD1 and HBD3 form well defined structures with backbone root mean square deviations of 0.451 and 0.616 Angstrom, respectively. The tertiary structures of all three beta-defensins are similar, with a short helical segment preceding a three-stranded anti-parallel beta-sheet. The surface charge density of each of the defensins is markedly different, with the surface of HBD3 significantly more basic. Analysis of the NMR data and structures led us to suggest that HBD3 forms a symmetrical dimer through strand beta2 of the beta-sheet. The increased anti-Staphylococcal activity of HBD3 may be explained by the capacity of the protein to form dimers in solution at low concentrations, an amphipathic dimer structure, and the increased positive surface charge compared with HBD1 and HBD2.