PROTEIN CONFORMATION SAMPLING USING ENERGY LANDSCAPE APPROACH

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 研究中心，而研究中心不一定是研究者所在的机构。 在哺乳动物细胞中，蛋白质最初表达为具有20种不同氨基酸的杂聚体。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如糖基化、甲基化或核苷酸化来实现的。这些修饰可以通过扰乱蛋白质的能量分布而导致蛋白质的构象变化，从而改变它们的功能。 在本文中，我们解决的能量和结构的后果，最重要的形式之一的可逆修改：磷酸化。在磷酸肽中，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节中非常频繁地发生，并且由于质谱的进步而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-蛋白质相互作用，而且可以允许使用单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，还可以全局改变蛋白质的三级结构，从而使磷酸化重置开关。

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.