ABSTRACT
Structure determination for membrane proteins has been extremely modest compared with soluble proteins. Among the more than 30,000 structures deposited in public databases, less than100 have been obtained for membrane proteins. The low success rate is mainly due to the difficulties in expression, purification, and crystallization of membrane proteins. Generally, the quantity and quality of recombinantly expressed membrane proteins have not been sufficient. Moreover, the solubilization and crystallization in the presence of detergents severely affect the yields and reduce the stability of purified proteins. Structural genomics approaches, where a large number of targets are processed in parallel, have provided new means of developing high-throughput (HT) methods for optimization of technologies facilitating structure determination of membrane proteins. The establishment of large national and international networks has enhanced the productivity and, hopefully, will provide the tools for solving many new structures of membrane proteins in the near future.
