A pulsed-field gradient NMR study of bovine pancreatic trypsin inhibitor self-association
A pulsed-field gradient NMR study of bovine pancreatic trypsin inhibitor self-association
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DOI：
10.1021/bi9622229
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发表时间：
1997-03-18
期刊：
影响因子：
2.9
通讯作者：
Mayo, KH
中科院分区：
文献类型：
--
作者：
Ilyina, E;Roongta, V;Mayo, KH
先前的研究对溶液中 BPTI 的聚集状态产生了相互矛盾的解释。在此，使用 BPTI 在各种温度、pH、盐、尿素条件和蛋白质浓度下进行了脉冲场梯度 NMR 自缔合测量。相对于标准蛋白质、溶菌酶、核糖核酸酶和泛素；扩散常数表明，BPTI 在浓度高于约 3 mg/mL 且低于 280 K 时发生二聚。在较高温度下，在高于 10 mg/mL 时观察到显着的自缔合。 pH 值和 NaCl 浓度变化明显缺乏显着影响，这表明电荷-电荷相互作用对聚集过程的贡献很小。相反，在非变性浓度的尿素 (2 M) 中，BPTI 表现为单体，表明疏水性和极性残基调节 BPTI 缔合。 BPTI 表面表明，虽然一侧带高电荷，但另一侧主要由疏水残基和一些亲水残基组成，作为 BPTI 自缔合的界面是可行的。
Previous studies have produced conflicting interpretations regarding the aggregation state of BPTI in solution. Here, pulsed-field gradient NMR self-association measurements have been performed with BPTI under a variety of temperature, pH, salt, urea conditions, and protein concentrations. Relative to the standard proteins, lysozyme, ribonuclease, and ubiquitin; diffusion constants indicate that BPTI dimerizes at concentrations above about 3 mg/mL and below 280 K. At higher temperatures, a marked self-association is observed above 10 mg/mL. The apparent lack of significant effects from variations in pH and NaCl concentration suggests minimal contribution to the aggregation process from charge-charge interactions. In contrast, in nondenaturing concentrations of urea (2 M), BPTI behaves as a monomer, suggesting that hydrophobic and polar residues modulate BPTI association. The BPTI surface shows that while one side is highly charged, the opposite side, composed mostly of hydrophobic and some hydrophilic residues, is feasible as an interface for BPTI self-association.