Study of biomolecular complex formation by heteronuclear multidimensional NMR

许多生物分子在具有生物活性时形成非共价复合物（超分子）。在信号系统中起作用的分子的情况下，非共价复合物的形成是触发一些重要生物过程的初始事件。虽然对这类复合物已经进行了许多研究，但对信号传导的详细机制知之甚少。本研究的目的是通过多维核磁共振技术来探索这种蛋白质-蛋白质复合物的结构和动力学。此外，我们还打算发展物理化学方法，这是基于沉降平衡测量，差示扫描量热法和表面等离子体共振，以调查复杂的形成机制。特别是，我们将注意力集中在BMP（骨形态发生蛋白）系统上。我们已经建立了BMP及其受体分子的细菌表达系统。纯化的重组BMP受体具有较高的结合亲和力，并通过多种理化方法对其进行了定量分析。定点诱变研究表明，BMP受体的某些氨基酸残基有助于复合物的形成。用异相多维NMR方法对BMP受体进行了完整的归属，并基本确定了BMP受体的溶液结构。换句话说，我们有强大的工具和方法来研究高（原子）分辨率的BMP-BMP受体复合物。

Many biomolecules form non-covalent complexes (super molecules) when they are biologically active. In the case of molecules that act in signaling systems, the formation of the non-covalent complex is the initial event that triggers some important biological process. Although many studies have been made on such complexes, little is known about the detailed mechanism of signaling. The purpose of this research project is to explore the structure and dynamics of such protein-protein complexes by multidimensional NMR techniques. Moreover, we also intend to develop physico-chemical methodologies, which are based on sedimentation equilibrium measurements, differential scanning calorimetry and surface plasmon resonance, to investigate the mechanism of complex formation. In particular, we are focusing our attention on the BMP(bone morphogenetic protein) system. We have established a bacterial expression system for BMP and its receptor molecules. The purified recombinant BMP receptor showed high binding affinity, which was analyzed quantitatively by several physico- chemical methods. Site directed mutagenesis studies have revealed that certain amino acid residues of the BMP receptor contribute to complex formation. Using heteronuclear multidimensional NMR methods, the assignments of the BMP receptor are complete and the solution structure of BMP receptor nearly determined. In other words, we have powerful tools and methods to investigate the BMP-BMP receptor complex at high (atomic) resolution.