在水溶液中对模型β-sheet发针进行光学光谱检查
Jovencio Hilario1, Jan Kubelka, Timothy A Keiderling
1Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607-7061, USA.
Journal of the American Chemical Society
|June 19, 2003
概括
设计的β发针具有特定的序列显示显著的β叶结构. 光谱数据和模拟证实了结构, (D) Pro-Gly证明了增强β片形成的优越转动动机.
科学领域:
- 生物化学 生物化学
- 频谱学是一种光谱学.
- 计算化学计算化学
背景情况:
- 贝塔毛刺是重要的蛋白质结构图案.
- 核磁共振研究表明,设计的具有β片结构.
- 加入了疏水集群和特定序列 (D) Pro-Gly,以促进转换.
研究的目的:
- 为了报告设计的β-hairpins的光学光谱数据.
- 为了比较 (D) Pro-Gly 与 Asn-Gly 的疗效,转向图案.
- 用理论模拟来验证光谱发现.
主要方法:
- 里埃变换红外光谱法 (FTIR) 光谱法
- 电子循环二元化 (ECD) 和振动循环二元化 (VCD) 光谱.
- Ab initio用于模拟的量子力学计算.
- 热和瓜尼丁化变性研究.
主要成果:
- FTIR,ECD和VCD光谱与高β片含量保持一致.
- 与Asn-Gly相比, (D) Pro-Gly序列显示出优越的β-表谱特征.
- Spectra显示了与理论模拟的定性一致,有助于模式分配.
- 混合溶剂诱导了增加的板结构.
- 变性化研究揭示了广泛展开的过渡,热变性化与热变性变性化有着不同的终点状态.
结论:
- 设计的β-hairpins表现出相当大的β-sheet结构.
- (D) Pro-Gly序列是促进β-hairpin转动和稳定的有效动机.
- 光谱和计算方法提供了对结构的强有力的表征.
- 环境条件 (溶剂) 和变质剂会影响发针结构和稳定性.
相关概念视频
Spectrophotometry: Introduction
Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a material as a function of the intensity and wavelength of the radiation. A spectrophotometer is a device used to measure the change in the radiation intensity caused by its interaction with the material.
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
UV–Vis Spectrum
When light passes through a substance, a portion of the light is absorbed while the remaining light is reflected or transmitted. If the molecule absorbs light between the wavelengths of 180–400 nm range, the UV spectrum is obtained, and if it absorbs light in the 400–780 nm wavelength range, the visible spectrum is obtained.
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the C=O stretching, is...
IR and UV–Vis Spectroscopy of Carboxylic Acids
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
Spectroscopy of Carboxylic Acid Derivatives
Infrared spectroscopy is primarily used to determine the types of bonds and functional groups. In carboxylic acid derivatives, a typical carbonyl bond absorption is observed around 1650–1850 cm−1. For esters, the absorption is recorded at around 1740 cm−1, while acid halides show the absorption at about 1800 cm−1. Another acid derivative, the acid anhydrides, exhibit two carbonyl absorption around 1760 cm−1 and 1820 cm−1, arising from the symmetrical and unsymmetrical carbonyl vibration.
In the...
In the...
UV–Vis Spectrometers
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell. Samples for...


