23 base pairs or 30 base pairs
||Mammalian tissue culture cell
||Shokolenko IN, Alexeyev MF. Mitochondrial DNA: A disposable genome? Biochim Biophys Acta. 2015 Sep1852(9):1805-9. doi: 10.1016/j.bbadis.2015.05.016 p.1806 right column top paragraphPubMed ID26071375
|| Farge G et al., Protein sliding and DNA denaturation are essential for DNA organization by human mitochondrial transcription factor A. Nat Commun. 2012 3: 1013. doi: 10.1038/ncomms2001PubMed ID22910359
||Primary source abstract: "Here [investigators] use a combination of single-molecule manipulation and fluorescence microscopy to show the nonspecific DNA-binding dynamics and compaction by TFAM." Primary source p.3 right column 2nd paragraph: "Assembly of TFAM nucleoprotein structures: Next, [investigators] studied how TFAM assembles into compact nucleoprotein structures. [They] started this investigation by determining the footprint of a single TFAM molecule on DNA, using a combination of optical tweezers and fluorescence microscopy. The fluorescence intensity of single Alexa-555-labelled TFAM monomers was quantified using photo-bleaching (Fig. 3a,b). Thereafter, [they] determined the total fluorescence intensity of a fully TFAM-coated DNA molecule (Fig. 3a) and converted this intensity to the number of TFAM monomers. This way, [they] found that the footprint of a TFAM monomer was 30.3 ± 0.3 bp (mean ± s.e., N = 23)."
||P.1806 right column top paragraph: "This high degree of compaction [of the mitochondrial DNA nucleoid] is achieved with the help of the mitochondrial transcription factor A (TFAM), a high mobility group (HMG)-box DNA binding protein with functions in mtDNA packaging, replication and transcription. This protein binds mtDNA with a footprint of 23 bp or 30 bp [primary source], and is present in mitochondria in 1,000-fold molar excess with respect to mtDNA molecules, which is sufficient for the complete coating of mtDNA [ref 5]." Please note-it appears that the measurement was made in vitro according to ref  of the primary source."