POWRE: Molecular Mechanisms of Binding of Gd(3+) Complexes to Biomolecules

SmirnovaMCB 0075042本研究的目的是了解磁共振成像（MRI）开发的顺磁性造影剂（PCA）与生物大分子、磷脂和蛋白质可逆结合的分子机制，以及这些相互作用对PCA弛豫率的影响。 增强MRI在临床上有着广泛的应用，是研究的有力工具。 在显微成像和发育生物学中出现了新的应用。 然而，对于PCA的结构与功能关系，特别是PCA与生物大分子可逆结合的分子机制，以及生物环境对PCA弛豫的影响，目前还知之甚少。 本研究将表征结合相互作用，并调查这些相互作用对PCA的弛豫性的影响，通过系统的研究一系列的镧系离子配合物（Gd（III）与不同的亲脂性相结合的光谱技术，包括荧光，核磁共振，和电子磁共振在多个和高磁场。 模型磷脂将被用来看看亲脂性如何影响PCA的非特异性与生物膜相互作用的能力，以及这些相互作用如何改变Gd（III）络合物的弛豫性。 PCA与人血清白蛋白的非共价结合将使用自旋标记EPR、荧光和HF EPR的组合来绘制白蛋白分子上的PCA结合位点，并研究这些复合物的亲脂性变化如何影响结合。 还将检查脂肪酸结合蛋白，其具有单一但与白蛋白非常不同的结合位点。 这是一个POWRE提案，它将允许作为物理化学家培训的PI将其技能扩展到分子生物学。

SmirnovaMCB 0075042The aim of this research is to understand molecular mechanisms of reversible binding of paramagnetic contrast agents (PCA's) developed for Magnetic Resonance Imaging (MRI) to biological macromolecules, phospholipids and proteins, and the effort of these interactions on relaxivity of PCA's. Contrast-enhanced MRI has wide applications in clinical work and is a powerful tool in research. New applications are emerging in microimaging and developmental biology. However not enough is known about structure-function relationships of PCS's, especially the molecular mechanisms of reversible binding of PCA to biological macromolecules, and the effects of biological environment on relaxivity of PCA's. This research will characterize the binding interactions and investigate the effect of these interactions on relaxivity of PCA's through systematic studies of a series of lanthanide ion complexes (Gd(III) with different lipophilicity by a combination of spectoscopic techniques, including fluorescence, nuclear magnetic resonance, and electron magnetic resonance at multiple and high magnetic fields. Model phospholipids will be used to see how lipophilicity affects the ability of PCA's to interact non-specifically with biological membranes and how these interactions change relaxivity of the Gd(III) complex. PCA non covalent binding with human serum albumin will use a combination of spin-labeling EPR, fluorescence, and HF EPR to map the PCA binding sites over the albumin molecule and to study how changes in lipophilicity of these complexes affects the binding. Fatty acid binding proteins, which have a single but very different binding site than albumin will also be examined. This is a POWRE proposal, which will allow the PI who is trained as a physical chemist to extend her skills into molecular biology.