(1). We have discovery a novel histidine switch in RAP that cell uses to mediate the binding/release of the low-density lipoprotein receptor related protein (LRP) in the receptor maturation process (Mol. Cell, 2006, 22(3):423-30). The discovery the histidine switch trail blazes a new way to sequester receptors. The mutants that we have made during the course of the study have potential therapeutic applications in treatment of diseases involved with the LRP receptors. During the course of this project, we have also completed the determination of the structure of protein RAP. RAP is a protein chaperone and plays an important role in folding/trafficking of the low-density lipoprotein receptors in cells. Due to the nature of the RAP structure, it has been extremely difficult to determine the 3D structure of RAP. Our group has successfully determined the 3D structure of RAP using a combination of the solution NMR and the Small Angle Neutron Scattering (SANS). The 3D structure of RAP provides the first insight into the structural basis of versatility of the protein. This result has been published in Prot. Sci., 2007, 16(8):1628-40. We will continue our studies of the roles of the LRP receptors in the Wnt/beta-catenin signaling pathway. We have successfully cloned and expressed the soluble extracellular domains of the LRP5 and LRP6 (LRP5/6) receptors on a large scale using the insect cells. At the present time, we are working on a practical procedure to purify the receptors on a large scale. I should point out that the pace of our research in this area depends on and is limited by the resource that was allocated to my section. (2). We have completed the structural and dynamics studies of protein L11 in free, in the L11-RNA binary and the L11-RNA-thiostrepton ternary complexes, and revealed the structural and dynamics basis for L11 to gate the movements of various components involved in the elongation in protein synthesis. This result is of fundamental importance in understanding the mechanism of the elongation/translocation reaction in the protein synthesis. This work has been published in J. Mol. Biol. 2007, 367(4), 1007-1022. (3). We have completed the development of the 3P program. The 3P program uses the residual dipolar couplings from a single alignment tensor to determine the backbone structure of a protein. A J. Magn. Res. article that presents a detailed description of rigorous theoretical treatment and the programs of the 3P method is in press. (4). The determination of the structure of a 3UTR RNA (100 nt) is well underway. At the present time, we have made several NMR samples with various isotope-labeling and mutation schemes; we have collected high quality X-ray small and wide angle scattering data sets of several RNA constructs at the National Argonne Laboratory; we are developing the computational protocol that is required to refine RNA structures with restraints of scattering data; we are recoding an arrays of solution NMR spectra that are required to elucidate structural details of RNA molecules in solution.; we have developed the initial structural model of the 3UTR RNA.
| Lee, Donghan; Walsh, Joseph D; Mikhailenko, Irina et al. (2006) RAP uses a histidine switch to regulate its interaction with LRP in the ER and Golgi. Mol Cell 22:423-30 |
| Walsh, Joseph D; Kuszweski, John; Wang, Yun-Xing (2005) Determining a helical protein structure using peptide pixels. J Magn Reson 177:155-9 |
| Walsh, Joseph D; Wang, Yun-Xing (2005) Periodicity, planarity, residual dipolar coupling, and structures. J Magn Reson 174:152-62 |
| Wu, YiBing; Migliorini, Molly; Walsh, Joseph et al. (2004) NMR structural studies of domain 1 of receptor-associated protein. J Biomol NMR 29:271-9 |
| Walsh, Joseph D; Cabello-Villegas, Javier; Wang, Yun-Xing (2004) Periodicity in residual dipolar couplings and nucleic acid structures. J Am Chem Soc 126:1938-9 |
| Cabello-Villegas, Javier; Giles, Keith E; Soto, Ana Maria et al. (2004) Solution structure of the pseudo-5' splice site of a retroviral splicing suppressor. RNA 10:1388-98 |
| Neamati, Nouri; Murthy, Manisha; Wang, Yun-Xing (2003) Preparation of DNA-protein complexes suitable for spectroscopic analysis. Methods Mol Med 85:185-202 |
| Wu, YiBing; Migliorini, Molly; Yu, Ping et al. (2003) 1H, 13C and 15N resonance assignments of domain 1 of receptor associated protein. J Biomol NMR 26:187-8 |
