TWO HMG DOMAINS OF YEAST MITOCHONDRIAL PROTEIN ABF2P HAVE DIFFERENT AFFINITY TO DNA

Maintaining mitochondrial genome integrity is essential for the viability of the whole organism. Mitochondrial genome mutations lead to muscular dystrophies, neurodegenerative diseases, and are associated with aging. In this work a baker's yeast (Saccharomyces cerevisiae) mitochondria model was used to investigate DNA-binding abilities of different domains of a mitochondrial Abf2p protein which participates in homologous recombination and reparation. A weak non-specific HMG1 binding to linear DNA and a specific HMG1 binding to a branched DNA with a dissociation constant of 510 nM have been discovered. The HMG2 domain itself does not bind to any DNA and either has other functions or demonstrates its DNA-binding activity in a full-length protein only.