S. H. Park

University of California, San Diego, San Diego, California, United States

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Publications (2)2.09 Total impact

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    ABSTRACT: NMR methods can be used to determine the structures of membrane proteins. Lipids can be chosen so that protein-containing micelles, bicelles, or bilayers are available as samples. All three types of samples can be aligned weakly or strongly, depending on their rotational correlation time. Solution NMR methods can be used with weakly aligned micelle and small bicelle samples. Solid-state NMR methods can be used with mechanically aligned bilayer and magnetically aligned bicelle samples.
    No preview · Article · Feb 2005 · Methods in Enzymology
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    ABSTRACT: Virus protein ā€œuā€ (Vpu) contributes to the virulence of HIV-1 infections of humans by enhancing the production and release of progeny virus particles. Its biological activities are associated with the two distinct structural domains of the protein. Since the entire polypeptide consists of only 81 amino acid residues, each of the biological activities is associated with a relatively small and well-defined structural entity. This suggests that the three-dimensional structure of the protein will lead to a detailed understanding of its biological functions, and potentially to the identification of small molecules that act as drugs by interfering with its functions (Miller and Sarver, 1997) as has been done for other HIV-1 encoded proteins (Turner and Summers, 1999; Wlodawer, 2002). The many structure determinations of HIV protease alone and complexed with inhibitors led to the development of the highly effective drugs that are a mainstay of current therapy for AIDS (Erickson and Burt, 1996; Vondrasek et al., 1997). Even though the protease is about 20% larger than Vpu, its structure was determined very soon after its discovery (Navia et al., 1989; Wlodawer et al., 1989), while the structure of Vpu is yet to be determined. The reasons that Vpu has not followed quickly in the path of protease have their roots in the most fundamental aspects of experimental structural biology and biochemistry. Vpu is a helical membrane protein, and it requires the presence of lipids and water to adopt its native functional structure. The lipids interfere with the formation of crystals for X-ray diffraction as well as the preparation of samples suitable for multidimensional solution NMR spectroscopy. In contrast, protease is a globular, soluble protein well suited for experimental structure determination by both X-ray crystallography and
    No preview · Chapter · Dec 2004