Characterization of Cl-Par-4: WT vs. Mutant

Presenter and Co-Authors

Samjhana Pandey, Old Dominion UniversityFollow
Krishna K. Raut, Old Dominion UniversityFollow
Andrea M. Clark, Old Dominion UniversityFollow
Antoine Baudin, The University of Texas Health Science Center at San AntonioFollow
Lamya Djemri, Old Dominion UniversityFollow
David S. Libich, The University of Texas Health Science Center at San AntonioFollow
Steven M. Pascal, Old Dominion UniversityFollow

College

The Graduate School

Department

Chemistry and Biochemistry

Graduate Level

Doctoral

Graduate Program/Concentration

Biomedical Sciences - Microbiology and Immunology

Publication Date

2023

DOI

10.25883/05r3-9b18

Abstract

Intrinsically disordered proteins (IDPs) play important roles in regulation of cell signaling pathways as well as cellular processes. Dysregulation of these proteins is associated with several human diseases. Prostate apoptosis response-4 (Par-4), a proapoptotic tumor suppressor protein, is categorized as an intrinsically disordered protein and downregulation of this protein has been reported in myriad of cancers including glioma, breast cancers, and prostate cancers. The caspase-cleaved fragment of Par-4 (cl-Par-4) plays an active role in tumor suppression by inhibiting several cell survival pathways.

Here, we employed site-directed mutagenesis to introduce a point mutation in the cl-Par-4 wildtype (WT) to generate the D313K cl-Par-4 mutant. We have characterized both the mutant and the WT using various biophysical techniques such as CD, DLS, and NMR to determine the effect of the D313K mutation. The results show that D313K cl-Par-4 attains a compact and well-folded helical conformation, possibly a tetramer, similar to that of the WT in presence of high salt at physiological pH. However, D313K does so with half the amount of salt required for the WT. This establishes that the substitution of a basic residue for an acidic residue at position 313 alleviates inter-helical charge repulsion between dimer partners and helps to stabilize the structural conformation.

Keywords

IDPs, cl-par-4, Tumor suppressor, Wildtype vs. mutant, Site-directed mutagenesis, Protein characterization, CD, DLS, NMR, Structural determination

Disciplines

Biochemistry | Structural Biology

Files

Recommended Citation

Pandey, Samjhana; Raut, Krishna K.; Clark, Andrea M.; Baudin, Antoine; Djemri, Lamya; Libich, David S.; and Pascal, Steven M., "Characterization of Cl-Par-4: WT vs. Mutant" (2023). The Graduate School Posters. 2.
https://digitalcommons.odu.edu/gradposters2023_gradschool/2