PROTEIN CONFORMATION SAMPLING USING ENERGY LANDSCAPE APPROACH

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在哺乳动物细胞中，蛋白质最初以含有20种不同氨基酸的异质聚合物的形式表达。然而，蛋白质通常需要更多种类的亚基。这种更大的多样性是通过共价翻译后修饰实现的，例如糖基化、甲基化或核苷酸基化。这些修饰可以通过扰乱蛋白质的能量格局从而改变其功能，从而导致蛋白质的构象变化。 在这篇文章中，我们讨论了可逆修饰最重要的形式之一：磷酸化的能量和结构后果。在磷肽中，丝氨酸、苏氨酸、酪氨酸和组氨酸的侧链极性氢可以被磷酰基取代。磷酸化在信号转导调控中经常发生，随着质谱学的进步，在整个基因组中越来越多地被注意到。直接的结构修饰不仅可以影响蛋白质之间的相互作用，而且可以利用单一结构域蛋白质构建构象开关。以NFAT调控结构域为例，我们发现这些变化不仅可以局部改变蛋白质的二级结构，还可以在整体上改变蛋白质的三级结构，从而允许磷酸化重新启动开关。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In mammalian cells, proteins are initially expressed as hetero-polymers with 20 types of different amino acids. Proteins, however, often need more varieties of subunits. This greater diversity is achieved by covalent post-translational modifications such as glycosylation, methylation, or nucleotidylation. These modifications can lead to conformational changes of the proteins by perturbing their energy landscape and thereby altering their functions. In this paper, we address the energetic and structural consequence of one of the most important forms of reversible modification: phosphorylation. In phosphopeptides, the side chain polar hydrogens of serine, threonine, tyrosine, and histidine can be replaced by phosphoryl groups. Phosphorylation occurs quite frequently in signal transduction regulation and is increasingly being noticed throughout the genome due to the advancements of mass spectrometry. Direct structural modifications not only may affect protein-protein interactions, but can allow conformational switches to be constructed using single domain proteins. Using the NFAT regulatory domain as an example, we show these changes can not only modify the secondary structure of the protein locally but also globally alter protein tertiary structure, thus allowing phosphorylation to reset the switch.