...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biopolymers: Original Research on Biomolecules and Biomolecular Assemblies >Raman optical activity characterization of native and molten globule states of equine lysozyme: Comparison with hen lysozyme and bovine alpha-lactalbumin
【24h】

Raman optical activity characterization of native and molten globule states of equine lysozyme: Comparison with hen lysozyme and bovine alpha-lactalbumin

机译：马溶菌酶的天然和熔融小球状态的拉曼光学活性表征：与母鸡溶菌酶和牛α-乳清蛋白的比较

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Vibrational Raman optical activity (ROA) spectra of the calcium-binding lysozyme from equine milk in native and nonnative states are measured and compared with those of the homologous proteins hen egg white lysozyme and bovine alpha-lactalbumin. The ROA spectrum of holo equine lysozyme at pH 4.6 and 22 degrees C closely resembles that of hen lysozyme in regions sensitive to backbone and side chain conformations, indicating similarity of the overall secondary and tertiary structures. However, the intensity of a strong positive ROA band at similar to 1340 cm(-1), which is assigned to a hydrated form of alpha helix, is more similar to that in the ROA spectrum of bovine alpha-lactalbumin than hen lysozyme and may be associated with the greater flexibility and calcium-binding ability of equine lysozyme and bovine alpha-lactalbumin compared with hen lysozyme. In place of a strong sharp positive ROA band at similar to 1300 cm(-1) in hen lysozyme that is assigned to an alpha-helix in a more hydrophobic environment, equine lysozyme shows a broader band centered at similar to 1305 cm(-1), which may reflect greater heterogeneity in some alpha-helical sequences. The ROA spectrum of apo equine lysozyme at pH 4.6 and 22 degrees C is almost identical to that of the hole protein, which indicates that loss of calcium has little influence on the backbone and side chain conformations, including the calcium-binding loop. From the similarity of their ROA spectra, the A state at pH 1.9 and both 2 and 22 degrees C and the apo form at pH 4.5 and 48 degrees C, which are partially folded denatured (molten globule or state A) forms of equine lysozyme, have similar structures that the ROA suggests contain much hydrated alpha helix. The A state of equine lysozyme is shown by these results to be more highly ordered than that of bovine alpha-lactalbumin, the ROA spectrum of which has more features characteristic of disordered states. A positive tryptophan ROA band at similar to 1551 cm(-1) in the native hole protein disappears in the A state, which is probably due to the presence of nonnative conformations of the tryptophans associated with a previously identified cluster of hydrophobic residues. (C) 2000 John Wiley & Sons, Inc. [References: 67]
机译：测量了马乳中天然和非天然状态下钙结合溶菌酶的振动拉曼光学活性（ROA）光谱，并将其与蛋清溶菌酶和牛α-乳清蛋白中的同源蛋白质进行了比较。 pH 4.6和22摄氏度时马整体溶菌酶的ROA谱图与母体和溶菌酶在对骨架和侧链构象敏感的区域中的ROA谱图非常相似，表明总体二级和三级结构相似。但是，强正ROA谱带的强度接近于1340 cm（-1），这被归为水合形式的α螺旋，比母鸡溶菌酶更类似于牛α-乳白蛋白的ROA光谱，可能与母鸡溶菌酶相比，马溶菌酶和牛α-乳白蛋白具有更大的柔韧性和钙结合能力。马溶菌酶代替了在更疏水的环境中分配给α-螺旋的母鸡溶菌酶中类似于1300 cm（-1）的强而尖锐的正ROA带，而马溶菌酶显示了一个更宽的带，集中在类似于1305 cm（-1）的位置），这可能反映出某些alpha螺旋序列中存在更大的异质性。载脂蛋白马溶菌酶在pH 4.6和22摄氏度下的ROA谱图与孔蛋白的ROA谱图几乎相同，这表明钙的损失对主链和侧链构象（包括钙结合环）几乎没有影响。根据其ROA光谱的相似性，pH为1.9且处于2和22摄氏度的A状态，以及pH处于4.5和48摄氏度的apo形式，它们是马溶菌酶的部分折叠变性（熔融小球或状态A）形式，具有相似的结构，因此ROA建议包含大量水合的α螺旋。这些结果表明，马溶菌酶的A状态比牛α-乳白蛋白的A状态更高，后者的ROA光谱具有无序状态的更多特征。天然孔蛋白中类似于1551 cm（-1）的色氨酸ROA阳性带以A状态消失，这可能是由于色氨酸的非天然构象与先前鉴定的疏水性残基簇相关。 （C）2000 John Wiley＆Sons，Inc. [参考：67]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号