Utilizing protein crystallography in the structural characterization of protein complexes

Abstract

The ATPase protein p97 plays an essential role in the healthy function of living cells. When defective proteins are detected by the cell, the endoplasmic reticulumassociated protein degradation pathway aids in the transport and ultimate degradation of these misfolded proteins before they can aggregate and cause problems for the host. P97 is a key player in this pathway by serving as the main source of energy by which these proteins are transported for destruction. Because p97 plays such an important role in the transport of defective proteins to maintain a healthy cell, it is important to not only study the protein itself, but also understand its relationship and binding with other proteins in the pathway. One such binding partner is Selenoprotein S, a protein that is responsible for recruiting p97 to the pathway. In this work, protein crystallography was utilized in an attempt to study the p97 and Selenoprotein S binding complex to ultimately solve the complex crystal structure. Outlined are preliminary successful crystallization conditions for p97 on its own and in complex with Selenoprotein S. These conditions can be used as starting points for further refinement to produce high quality protein crystals for X-Ray analysis.