Expression, purification, and in vitro mitochondrial interaction analysis of full-length and truncated human tumor suppresser p53

p53 is a potent tumor suppressor which can prevent the propagation of cells carrying oncogenic lesions via a multitude of pathways. Besides the transactivation of downstream genes encoding proapoptotic proteins, p53 is also able to physically interact with mitochondria and induce apoptosis through a so called transcriptional-independent pathway. In this study, we described a quick method for the expression and purification of soluble recombinant p53 and its different truncations in E. coli. These proteins are able to interact with mitochondria and induce mitochondrial outer membrane permeabilization and associated downstream apoptotic events in a cell-free apoptosis analysis system. DNA binding domain of p53 is essential for its direct interaction with isolated mitochondria in vitro. Abbreviations: MOMP: mitochondrial outer membrane permeabilization; DBD: DNA binding domain; PCR: polymerase chain reaction; LB medium: Luria Bertani medium; IPTG: isopropyl β-d-thiogalactoside; Ni 2+ -NTA resin: nickel-nitrilotriacetic acid resin; PVDF membrane: polyvinylidene difluoride membrane;