The character of protein-nucleic interaction in relation to the mtDNA-membrane complex.

Specific sites that interact with structural proteins of the mitochondrial inner membrane were found in mitochondrial DNA (mtDNA) of rat liver. Analysis of the isolated DNA fragments revealed their capacity to form a complex with membrane proteins in vitro and allowed the detection of a protein with a molecular weight 40,000. The size of the fragments was found to be 12-18 nucleotide pairs with an average molecular weight 10,000 MtDNA sites recognized by membrane protein proved to be quite unique in having a secondary structure, a high content of AT sequences (82%) and oligopyrimidine blocks. It was shown that the light mtDNA strand, rich in adenine, is 60% more active in the binding with membrane mitochondria than the heavy one.