Automated 2D IR spectroscopy using a mid-IR pulse shaper and application of this technology to the human islet amyloid polypeptide
Automated 2D IR spectroscopy using a mid-IR pulse shaper and application of this technology to the human islet amyloid polypeptide
复制标题
DOI：
10.1073/pnas.0700804104
复制
发表时间：
2007-09-04
影响因子：
11.1
通讯作者：
Zanni, Martin T.
中科院分区：
文献类型：
--
作者：
Shim, Sang-Hee;Strasfeld, David B.;Zanni, Martin T.
可编程的中红外脉冲整形器大大提高了数据收集的简易性、速度和准确性，从而增强了2D IR光谱阐明时间演变结构的能力。传统的采集二维红外光谱的方法难以实现，导致峰形失真，并导致较差的时间分辨率和/或相位问题。我们报道了用计算机控制的锗声光调制器采集二维红外光谱的几种方法，它克服了上述问题。每种方法的准确度和分辨率都是通过使用具有明确线形的模型金属羰基化合物来评估的。此外，现在可以使用相位循环来极大地减轻来自非均质样品的背景散射。有了这些方法，我们应用2D IR光谱研究了与2型糖尿病相关的聚集性人胰岛淀粉样多肽(NAPP)的淀粉样纤维结构多样性。二维红外光谱表明，β-折叠纤维具有较大的结构分布，表现为非均匀展宽的β-折叠峰和与无规卷曲构象的强烈耦合。结构多样性是hIAPP的一个重要特征，因为它可能是部分折叠的多肽导致的疾病。在hIAPP上的这个实验是一个例子，说明计算机生成2D IR脉冲序列是实现2D IR光谱自动化的关键一步，从而可以快速实现新的脉冲序列，并可以更容易地研究不同范围的系统。
The capability of 2D IR spectroscopy to elucidate time-evolving structures is enhanced by a programmable mid-IR pulse shaper that greatly improves the ease, speed, and accuracy of data collection. Traditional ways of collecting 2D IR spectra are difficult to implement, cause distorted peak shapes, and result in poor time resolution and/or phase problems. We report on several methods for collecting 2D IR spectra by using a computer-controlled germanium acoustooptic modulator that overcomes the above problems. The accuracy and resolution of each method is evaluated by using model metal carbonyl compounds that have well defined line-shapes. Furthermore, phase cycling can now be employed to largely alleviate background scatter from heterogeneous samples. With these methods in hand, we apply 2D IR spectroscopy to study the structural diversity in amyloid fibers of aggregated human islet amyloid polypeptide (NAPP), which is involved with type 2 diabetes. The 2D IR spectra reveal that the beta-sheet fibers have a large structural distribution, as evidenced by an inhomogeneously broadened beta-sheet peak and strong coupling to random coil conformations. Structural diversity is an important characteristic of hIAPP because it may be that partly folded peptides cause the disease. This experiment on hIAPP is an example of how computer generation of 2D IR pulse sequences is a key step toward automating 2D IR spectroscopy, so that new pulse sequences can be implemented quickly and a diverse range of systems can be studied more easily.