Conformational dynamics and stability of HP35 studied with 2D IR vibrational echoes.
Conformational dynamics and stability of HP35 studied with 2D IR vibrational echoes.
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DOI：
10.1021/ja303017d
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发表时间：
2012-07-25
影响因子：
15
通讯作者：
Fayer, Michael D.
中科院分区：
文献类型：
--
作者：
Chung, Jean K.;Thielges, Megan C.;Fayer, Michael D.
二维红外（2D IR）振动回波光谱被用来测量快速动力学的两个变种的鸡绒毛头35（HP 35）使用CN的氰基苯丙氨酸残基插入在疏水核心作为振动探针。对野生型序列内的单CN标记肽（HP 35-P）和双CN标记肽（HP 35-P2）以及含有单标记氰基苯丙氨酸和两个正亮氨酸突变的HP-35（HP 35-P NleNle）进行实验。在单CN和双CN标记的HP 35中测得的动力学之间存在显著的相似性，表明额外CN振动探针的存在不会显著改变小肽的动力学。用正亮氨酸取代两个赖氨酸残基，通过用非极性残基取代带电残基，稳定疏水核，显著提高了HP 35的稳定性。二维红外实验的结果表明，HP 35-P的动力学明显快于HP 35-P NleNle。这些观察结果表明，疏水核中较慢的结构波动，表明结构更紧密的核，可能是HP 35-P NleNle稳定性增加的重要贡献因素。
Two-dimensional infrared (2D IR) vibrational echo spectroscopy was used to measure the fast dynamics of two variants of chicken villin headpiece 35 (HP35) using the CN of cyanophenylalanine residues inserted in the hydrophobic core as a vibrational probe. Experiments were performed on both singly (HP35-P) and doubly CN-labeled peptide (HP35-P2) within the wild-type sequence, as well as on HP-35 containing a singly labeled cyanophenylalanine and two norleucine mutations (HP35-P NleNle). There is a remarkable similarity between the dynamics measured in singly and doubly CN labeled HP35, demonstrating that the presence of an additional CN vibrational probe does not significantly alter the dynamics of the small peptide. The substitution of two lysine residues by norleucines markedly improves the stability of HP35 by replacing charged with nonpolar residues, stabilizing the hydrophobic core. The results of the 2D IR experiments reveal that the dynamics of HP35-P are significantly faster than HP35-P NleNle. These observations suggest that the slower structural fluctuations in the hydrophobic core, indicating a more tightly structured core, may be an important contributing factor to HP35-P NleNle’s increased stability.
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