pH-dependent interactions and the stability and folding kinetics of the N-terminal domain of L9. Electrostatic interactions are only weakly formed in the transition state for folding.
pH-dependent interactions and the stability and folding kinetics of the N-terminal domain of L9. Electrostatic interactions are only weakly formed in the transition state for folding.
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pH 依赖性相互作用以及 L9 N 末端结构域的稳定性和折叠动力学。
DOI：
10.1006/jmbi.2000.3752
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发表时间：
2000
影响因子：
5.6
通讯作者：
D. Raleigh
中科院分区：
文献类型：
--
作者：
D. Luisi;D. Raleigh
通过确定不同 pH 条件的影响，研究了静电相互作用在核糖体蛋白 L9 (NTL9) N 端结构域的稳定性和折叠中的作用。使用尿素变性和热解折叠实验来测量 18 个不同 pH 值（范围从 pH 1.1 到 pH 10.5）下的折叠自由能 DeltaG 度。在 pH 2.1 和 pH 9.5 之间的 19 个 pH 值下测量折叠速率，并使用停流荧光实验在该范围内的 15 个 pH 值下测定解折叠速率。该蛋白质在 pH 5.5 至 7.5 之间最为稳定，DeltaG 度值 = 4.45 kcal mol(-1)。折叠率在 pH 5.5 时达到最大值，但折叠率随 pH 值的变化相对较小。在 2.1 至 5.5 的 pH 范围内，折叠率略有增加，ln (k(f)) 从 5.1 变化至 6.8。然而，稳定性的变化更为显着，pH 2.0 和pH 5.4 之间的差异为2.6 kcal mol(-1)。稳定性的变化主要是由于低 pH 值下展开的屏障较小。展开速率的自然对数在 pH 2.1 和 pH 5.5 之间变化约四个单位。 pH 值高于 7.5 时，蛋白质的稳定性会降低，而且这种变化主要是由于解折叠速率的变化。 ln (k(f)) 在 pH 5.5 至 pH 9.5 之间变化小于 1 个单位，而 DeltaG 度在 pH 5. 4 至 pH 10.0 范围内减少 2.4 kcal mol(-1)，这对应于 ln K(eq) 的变化为 4.0。这些研究表明，pH 依赖性相互作用对蛋白质的整体稳定性有显着贡献，但对折叠动力学影响很小，表明静电相互作用在折叠过渡态中形成较弱。
The role of electrostatic interactions in the stability and the folding of the N-terminal domain of the ribosomal protein L9 (NTL9) was investigated by determining the effects of varying the pH conditions. Urea denaturations and thermal unfolding experiments were used to measure the free energy of folding, DeltaG degrees, at 18 different pH values, ranging from pH 1.1 to pH 10.5. Folding rates were measured at 19 pH values between pH 2.1 and pH 9.5, and unfolding rates were determined at 15 pH values in this range using stopped-flow fluorescence experiments. The protein is maximally stable between pH 5.5 and 7.5 with a value of DeltaG degrees =4.45 kcal mol(-1). The folding rate reaches a maximum at pH 5.5, however the change in folding rates with pH is relatively modest. Over the pH range of 2.1 to 5.5 there is a small increase in folding rates, ln (k(f)) changes from 5.1 to 6.8. However, the change in stability is more dramatic, with a difference of 2.6 kcal mol(-1) between pH 2.0 and pH 5.4. The change in stability is largely due to the smaller barrier for unfolding at low pH values. The natural log of the unfolding rates varies by approximately four units between pH 2.1 and pH 5.5. The stability of the protein decreases above pH 7.5 and again the change is largely due to changes in the unfolding rate. ln (k(f)) varies by less than one unit between pH 5.5 and pH 9.5 while DeltaG degrees decreases by 2.4 kcal mol(-1) over the range of pH 5. 4 to pH 10.0, which corresponds to a change in ln K(eq) of 4.0. These studies show that pH-dependent interactions contribute significantly to the overall stability of the protein but have only a small effect upon the folding kinetics, indicating that electrostatic interactions are weakly formed in the transition state for folding.
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影响因子：
2.9
作者：
S. Spector;Minghui Wang;S. A. Carp;J. Robblee;Z. Hendsch;R. Fairman;B. Tidor;D. Raleigh
通讯作者：
S. Spector;Minghui Wang;S. A. Carp;J. Robblee;Z. Hendsch;R. Fairman;B. Tidor;D. Raleigh
影响因子：
2.9
作者：
PACE, CN;LAURENTS, DV;THOMSON, JA
通讯作者：
THOMSON, JA
影响因子：
5.6
作者：
GILSON, MK;RASHIN, A;HONIG, B
通讯作者：
HONIG, B
影响因子：
5.6
作者：
Kumar, S;Nussinov, R
通讯作者：
Nussinov, R
影响因子：
2.9
作者：
Cavagnero, S;Debe, DA;Chan, SI
通讯作者：
Chan, SI