The Accessory Subunit of Xenopus laevis Mitochondrial DNA Polymerase γ Increases Processivity of the Catalytic Subunit of Human DNA Polymerase γ and Is Related to Class II Aminoacyl-tRNA Synthetases

• DOI: 10.1128/mcb.19.6.4039
• Publication Date: 2015-10-26T10:18:57Z
• Authors: José A. Carrodeguas; Ryuji Kobayashi; Susan E. Lim; William C. Copeland; Daniel F. Bogenhagen
• Keywords: Processivity; DNA clamp; DNA polymerase II; DNA polymerase delta

Peptide sequences obtained from the accessory subunit of Xenopus laevis mitochondrial DNA (mtDNA) polymerase gamma (pol gamma) were used to clone cDNA encoding this protein. Amino-terminal sequencing protein indicated presence a 44-amino-acid targeting sequence, leaving predicted mature with 419 amino acids and molecular mass 47.3 kDa. This is associated larger, catalytic in preparations active mtDNA polymerase. The small exhibits homology its human, mouse, Drosophila counterparts. Interestingly, significant glycyl-tRNA synthetases prokaryotic organisms reveals likely evolutionary relationship. Since attempts produce an enzymatically recombinant pol have not been successful, we tested effects adding enzyme human purified baculovirus-infected insect cells. These experiments provide first functional evidence that stimulates processive synthesis by under physiological salt conditions.