The structure and DNA-binding properties of Mgm101 from a yeast with a linear mitochondrial genome

• Published in: Nucleic acids research 2016-03, Vol.44 (5), p.2227-2239
• Main Authors: Pevala, Vladimír, Truban, Dominika, Bauer, Jacob A, Košťan, Július, Kunová, Nina, Bellová, Jana, Brandstetter, Marlene, Marini, Victoria, Krejčí, Lumír, Tomáška, Ľubomír, Nosek, Jozef, Kutejová, Eva
• Format: Article
• Language: English
• Subjects: Candida - genetics; Candida - metabolism; Candida parapsilosis; Cell Nucleus - genetics; Cell Nucleus - metabolism; Cloning, Molecular; DNA, Fungal - genetics; DNA, Fungal - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Escherichia coli - genetics; Escherichia coli - metabolism; Gene Expression; Gene Expression Regulation, Fungal; Genetic Complementation Test; Genome Integrity, Repair and; Genome, Fungal; Genome, Mitochondrial; Mitochondria - genetics; Mitochondria - metabolism; Mitochondrial Proteins - genetics; Mitochondrial Proteins - metabolism; Mutation; Protein Binding; Protein Multimerization; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Recombination, Genetic; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Telomere - chemistry; Telomere - metabolism; Telomere Homeostasis
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkv1529

To study the mechanisms involved in the maintenance of a linear mitochondrial genome we investigated the biochemical properties of the recombination protein Mgm101 from Candida parapsilosis. We show that CpMgm101 complements defects associated with the Saccharomyces cerevisiae mgm101-1(ts) mutation and that it is present in both the nucleus and mitochondrial nucleoids of C. parapsilosis. Unlike its S. cerevisiae counterpart, CpMgm101 is associated with the entire nucleoid population and is able to bind to a broad range of DNA substrates in a non-sequence specific manner. CpMgm101 is also able to catalyze strand annealing and D-loop formation. CpMgm101 forms a roughly C-shaped trimer in solution according to SAXS. Electron microscopy of a complex of CpMgm101 with a model mitochondrial telomere revealed homogeneous, ring-shaped structures at the telomeric single-stranded overhangs. The DNA-binding properties of CpMgm101, together with its DNA recombination properties, suggest that it can play a number of possible roles in the replication of the mitochondrial genome and the maintenance of its telomeres.