The long-term objective of this work is the development of rapid and general methods for generating one- and two-dimensional protein crystals for rapid structural analysis of proteins at medium (10Å) resolution.  Our strategies are designed to utilize polyhistidine tags (his-tag) that are commonly used to isolate and purify proteins after expression.  Two protein classes are under investigation:

                 Soluble proteins.   Monolayers, hybrid bilayers, & 1D lipid phases containing metal chelation sites that are capable of binding his-tag proteins are used to nucleate and crystallize the protein for confocal microscopy, AFM, cryo-SEM and cryoTEM analysis.  A diverse family of chelating lipids and nanomaterials are being utililzed in this project, including novel non-covalent amphiphiles based on host-guest chemistry & nitrilotriacetic acid-modified polyrotaxanes.

                 Integral membrane proteins (IMP). Approximately 60% of current drug targets are integral membrane proteins.  At present, there are only ~130 atomically resolved IMP structures—accounting for less than 0.5% of the high resolution structures found in the Protein Data Bank.  We are synthesizing and testing a new class of polyvalent chelators for their abililty to direct the crystallization of his-tag IMP.

References

E. Barklis, J. McDermott, S. Wilkens, E. Schabtach, M. Schmid, S. Fuller, S. Karanjia, Z. Love, R. Jones, X. Zhao, Y. Rui & D. H. Thompson, “Structural Analysis of Membrane-Bound Retrovirus Capsid Proteins” EMBO Journal 1997 16, 1199-1213.

 E. Barklis, J. McDermott, S. Wilkens, S. Fuller, & D. H. Thompson, “Organization of HIV-1 Capsid Proteins on a Lipid Monolayer” Journal of Biological Chemistry 1998 273, 7177-7180.

 M. Zhou, S. Haldar, J. Franses, J.-M. Kim & D. H. Thompson, “Synthesis and Self-Assembly Properties of Acylated Cyclodextrins and Nitrilotriacetic Acid (NTA)-Modified Inclusion Ligands for Interfacial Protein Crystallization”, Supramolecular Chemistry 2005 17, 101-111.

 D. H. Thompson, M. Zhou, J. Grey, H.-k. Kim, “Design, Synthesis and Performance of NTA-Modified Lipids as Templates for Histidine-Tagged Protein Crystallization”, Chemistry Letters 2007 36, 956-975.