Biophysical Characterization of Full Length EXOG a Human Mitochondrial Inner Membrane Nuclease

Abstract

Human mitochondrial nuclease, EXOG (hEXOG), is a part of mtDNA repair machinery. It is anchored to the inner mitochondrial membrane via N-terminal transmembrane domain. Besides its endo- and exonucleolytic activities it is proposed to serve as a scaffold for assembly of the mtDNA repair complex on mitochondrial inner membrane. Recently the X-ray crystal structures of NΔ58 hEXOG in apo and DNA-bound forms were solved and activity of truncated mutant, without transmembrane part of the protein, was determined. Here we show that full-length hEXOG can be purified and refolded in the presence of different detergents and model membranes. We show that the nature of these biomimetic systems has a significant effect on the stability, structure and function of hEXOG.