Infrared study of the stability and folding kinetics of a series of β-hairpin peptides with a common NPDG turn.
Infrared study of the stability and folding kinetics of a series of β-hairpin peptides with a common NPDG turn.
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DOI：
10.1021/jp2046867
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发表时间：
2011-12-29
影响因子：
3.3
通讯作者：
Oyola, Rolando
中科院分区：
文献类型：
--
作者：
Xu, Yao;Du, Deguo;Oyola, Rolando
采用傅里叶变换红外光谱（FTIR）和激光诱导温度跃变（T-jump）结合红外检测技术研究了一系列具有I型[3：5] NPDG转角的15个β-发夹结构的热稳定性和折叠动力学。在肽序列SEXYXNPDGTWTXTE中的位置3、5或13处进行突变，其中X表示突变位置，以研究疏水相互作用在确定β-发夹折叠的热力学和动力学性质中的作用。热稳定性研究表明，所有肽的广泛的热折叠/解折叠转变。T-jump研究表明，这些β-发夹肽在不到2 μs内折叠。此外，折叠和解折叠速率常数随着疏水相互作用强度的增加而降低。在动力学上，疏水相互作用对解折叠速率的影响比折叠速率的影响更大。Φ值分析表明，侧链间的疏水相互作用主要在折叠过程中过渡态区的后半部分形成。总之，结果表明，这些β-发夹的天然结构的形成取决于疏水簇的正确拓扑结构。除了先前的研究表明转角区域的形成是折叠的关键过程之外，疏水性塌陷过程也可能在β-发夹折叠过程中起关键作用。
The thermal stability and folding kinetics of a series of 15-residue β-hairpins with a common Type I [3:5] NPDG turn were studied using Fourier transform infrared spectroscopy (FTIR) and laser-induced temperature-jump (T-jump) with infrared detection, respectively. Mutations at positions 3, 5 or 13 in the peptide sequence SEXYXNPDGTWTXTE, where X represents the position of mutation, were performed to study the roles of hydrophobic interactions in determining the thermodynamic and kinetic properties of β-hairpin folding. The thermal stability studies show a broad thermal folding/unfolding transition for all the peptides. T-jump studies indicate that these β-hairpin peptides fold in less than 2 μs. In addition, both folding and unfolding rate constants decrease with increasing strength of hydrophobic interactions. Kinetically, the hydrophobic interactions have more significant influence on the unfolding rate than the folding rate. Φ-value analysis indicates that the hydrophobic interactions between the side chains are mainly formed at the latter part of the transition state region during the folding process. In summary, the results suggest that the formation of the native structure of these β-hairpins depends on the correct topology of the hydrophobic cluster. Besides the formation of the turn region as a key process for folding as suggested by previous studies, a hydrophobic collapse process may also play a crucial role during β-hairpin folding.
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影响因子：
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作者：
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DOI：
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