W0415
The Development and Application of Membrane Protein
Crystallization Screens Based Upon Detergent Phase Behavior. Michael
Wiener, Dept. of Molecular Physiology and Biological Physics, Univ. of Virginia,
P.O. Box 800736, Charlottesville, VA 22908-0736.
The elucidation of integral membrane protein structures is a
frontier area of modern structural biology. Integral membrane proteins comprise
15-30% of the ORFs of an organism’s genome, are the current (and likely
future) target of the majority of drugs, and carry out many biological processes
of fundamental import. However, nontrivial technical challenges have impeded
progress in this field. One challenge is the production of suitable quantities
of membrane proteins, especially eukaryotic membrane proteins, for
crystallization. Another challenge is obtaining three-dimensional crystals of
sufficient long-range order to permit structure determination. A critical
consideration is that the entity being crystallized is a protein-detergent
complex (PDC), i.e., a protein encircled by a torus of detergent molecules.
Therefore, both protein and detergent properties impact the crystallization
outcome. A principal hypothesis of our research is that the properties of
detergent and protein/detergent solutions, such as their phase behavior and
critical phenomena, play a significant role during membrane protein
crystallization. Therefore, the characterization of these properties, and the
subsequent incorporation of this information into crystallization experiments,
will enable the more successful formation of well-ordered membrane protein
crystals for structure determination. We are utilizing a variety of techniques
for the development and implementation of novel detergent-specific membrane
protein crystallization screens. Relevant physical-chemical properties of
detergents will be discussed in the context of screen design, and some results
from these screens will be presented.