This project entails structure and dynamics studies of biological macromolecules through nuclear magnetic resonance (NMR) spectroscopy. The present foci are polysaccharides, important vaccine components whose structure is poorly understood, and HIV-related peptides. NMR was employed to detect changes in the spectra of carbohydrates such as sucrose and lactose. These simple disaccharides serve as models and provide the basis for structural studies of oligo- and polysaccharides. Dissolving carbohydrates in liquid crystalline media orients them in a magnetic field, and this orientation provides important, direct structural data from internuclear dipolar interactions, which previously had to be inferred. Preliminary work indicates that the two rings in sucrose are perpendicular. The solution structure of sucrose is still hotly debated, and these results answer important questions in this debate. Upon proving this methodology robust in the model systems, we will study polysaccharide structure in a similar fashion. Another project is the solution structure of eptides from gp41. Our goal in this work is to characterize the structure of the peptides and use them to understand the interactions which must occur to lock HIV-fusion. This important region of gp41 is an excellent target or anti-HIV therapy because it is highly conserved across many isolates of HIV, and implied in studies as the region that is bound by gp41 C-terminal peptides to block viral fusion. DP-107 is known to have a helical character in solution, which makes it a good candidate for solution-state structural studies. To study this peptide in solution, isotopic labels need to be incorporated (15N, and 13C) through over-expression in E. Coli. To this end Dr. Weiss has expressed DP-107 in unlabeled media and a purification scheme has been developed to provide pure DP-107. We established a collaboration with Dr. Paul Wingfield at the Protein Expression Lab (NIAMS, NIH) to obtain labeled DP-107 for structural studies. Published Manuscripts: Flexibility and Function in HIV Protease-Dynamics of the HIV-1 Protease Bound to the Asymmetric Inhibitor Kynostatin 272 (KNI-272) . Daron Freedberg, Yun-Xing Wang, Stephen J. Stahl, Joshua D. Kaufman, Paul T. Wingfield, Yoshiaki Kiso, Dennis A. Torchia, Journal of American Chemical Society, 120, 7916-7923 (1998)
