| | Category | BI | L09 | Computational and Experimental Studies of Human SLX4 Protein BTB |
| | domain |
| | Abstract | As the race to cure cancer reaches a feverish pitch, being able to repair |
| | DNA and ultimately cure cancer is of the utmost importance. The human |
| | SLX4 (Synthetic Lethal of Unknown Function) protein serves as a scaffold |
| | protein which associates with other proteins to execute multiple functions |
| | in DNA repair. It contains an evolutionarily conserved BTB domain, a |
| | versatile protein-protein interaction module. To investigate the structure |
| | and function of SLX4 protein, homology modeling was used to create a 3D |
| | structure of the BTB domain in SLX4. Searching a template library yielded |
| | one template which shares a 21% sequence similarity. This template was |
| | used to generate a 3D model for the BTB-SLX4 domain which consists of |
| | five alpha-helices and three beta-sheets. The alpha-helices and beta- |
| | sheets arrange in the order of beta1-beta2-alpha1-alpha2-beta3-alpha3- |
| | alpha4-alpha5, representing the conserved core BTB fold. A recombinant |
| | protein (rBTB-SLX4) was designed to include this core BTB fold and |
| | additional alpha-helices at both the N- and C-terminus. During our |
| | experiment, rBTB-SLX4 was cloned, expressed and purified from E. coli. |
| | Limited proteolysis of rBTB-SLX4 revealed that Trypsin removes 44 amino |
| | acids from C-terminus of protein. We were able to show that this Trypsin- |
| | digested rBTB-SLX4 protein is responsible for protein-protein interactions |
| | in vitro using the cross-linking reagent DSS. Protein cross-linking analysis |
| | showed dimerization is the predominant form of interaction. Together, |
| | these experiments demonstrate that the BTB domain of SLX4 allows |
| | multiple copies of protein to interact with each other. |
| | Bibliography | 1) Svendsen, JM et al (10 July 2009). Mammalian BTBD12/SLX4 assembles |
| | a Holliday junction resolvase and is required for DNA repair. Cell 138 (1): |
| | 63–77 |
| | |
| | 2) Peter J Stogios et al (2005) Sequence and structural analysis of BTB |
| | domain proteins. Genome Biology 6:R82 3) Arnold K., Bordoli L., Kopp J., |
| | and Schwede T. (2006). The SWISS-MODEL Workspace: A web-based |
| | environment for protein structure homology modelling. Bioinformatics, |
| | 22,195-201. |