SELF ASSOCIATION OF STREPTOMYCES SUBTILISIN INHIBITOR - SEDIMENTATION EQUILIBRIUM AND H-1-NMR STUDIES
SELF ASSOCIATION OF STREPTOMYCES SUBTILISIN INHIBITOR - SEDIMENTATION EQUILIBRIUM AND H-1-NMR STUDIES
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DOI：
10.1093/oxfordjournals.jbchem.a122183
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发表时间：
1987-12-01
影响因子：
2.7
通讯作者：
AKASAKA, K
中科院分区：
文献类型：
--
作者：
INOUE, T;AKASAKA, K
结合沉降平衡分析和核磁共振氢谱研究了分子量为23，000的二聚体蛋白质链霉菌枯草杆菌蛋白酶抑制剂在水溶液中的自缔合。一个显着程度的自缔合，发现使用沉降平衡法在5和20毫克/毫升之间的浓度范围内。此外，使用1H NMR光谱结合沉降平衡法使我们能够研究在更高的浓度范围内（高达60 mg/ml或更高）的自缔合。在10-40 mg/ml浓度范围内的自缔合反应相当好地符合“连续聚合模型”，其中聚合反应的每个步骤由向先前形成的聚合物物质中加入一种枯草杆菌链霉菌蛋白酶抑制剂的固有二聚体组成，所有步骤共有的平衡常数为400 M-1。 1H NMR化学位移和谱线增宽数据表明，二聚体-二聚体相互作用可能涉及该抑制剂的反应位点片段，而蛋白质结构的主要部分没有显著的构象变化。
The self association of Streptomyces subtilisin inhibitor, a dimeric protein molecule of MW 23,000 in an aqueous environment has been investigated by the combined use of sedimentation equilibrium analysis and 1H nuclear magnetic resonance (NMR) spectroscopy. A significant degree of self association was found using the sedimentation equilibrium method in the concentration range between 5 and 20 mg/ml. Furthermore, the use of 1H NMR spectroscopy in conjunction with the sedimentation equilibrium method enabled us to study the self association in a much higher concentration range (up to 60 mg/ml or more). The self association reaction in the concentration range of 10-40 mg/ml fits reasonably well a "successive polymerization model" in which each step of the polymerization reaction consists of the addition of one intrinsic dimer of Streptomyces subtilisin inhibitor to the previously formed polymeric species, with an equilibrium constant common to all the steps of 400 M-1. The 1H NMR chemical shift and line broadening data show that the dimer-dimer interaction probably involves the reactive-site segment of this inhibitor without a significant conformational change in the major part of the protein structure.