Purification of an Abf2p-like protein from mitochondrial nucleoids of yeast Pichia jadinii and its role in the packaging of mitochondrial DNA.
A 26-kDa protein with highly basic pI was purified from the mitochondrial (mt-) nucleoids of the yeast Pichia jadinii by a combination of acid extraction, hydroxyapatite chromatography and DNA-cellulose chromatography. The 26-kDa protein has the ability to introduce a supercoil into circular plasmid DNA in the presence of topoisomerase I and to package mtDNA into nucleoid-like aggregates. The mt-nucleoids isolated from P. jadinii cells were disassembled in the presence of 2 M NaCl and reassembled into nucleoid-like aggregates by the removal of the salts. During the course of the reassembly of the mt-nucleoids, three specific proteins of 20 kDa, 26 kDa and 56 kDa predominantly precipitated after the centrifugation of the reassembled mt-nucleoids. These results suggest that the 26-kDa protein of P. jadinii has a similar function in the packaging of mtDNA to Abf2p, a major mitochondrial DNA-binding protein in Saccharomyces cerevisiae.
Miyakawa
Isamu
I
Department of Physics, Biology, and Informatics, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan. miyakawa@yamaguchi-u.ac.jp
Yawata
Kei
K
D042003:DNA Packaging / Q000502:physiology*; D004272:DNA, Mitochondrial / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008928:Mitochondria / Q000378:metabolism*; D010843:Pichia / Q000166:cytology* / Q000378:metabolism*
D004272:DNA, Mitochondrial; D005656:Fungal Proteins