Skip to main content
. Author manuscript; available in PMC: 2017 May 9.
Published in final edited form as: Enzymes. 2016 May 9;39:255–292. doi: 10.1016/bs.enz.2016.03.006

Figure 5.

Figure 5

Dimerization of vertebrate Pol γ-β via the formation of the four-helix bundle structure. A, Amino acid sequence alignment indicates the presence of the HLH-3β domain (boxed) in all species of Vertebrata and possibly in a few other animal groups. B, Comparison of the crystal structure of the human Pol γ-β dimer and structural models for Pol γ-β of Trichoplax adhaerens, Strongylocentrotus purpuratus, Drosophila melanogaster and Ciona intestinalis, showing that only vertebrate Pol γ-β can fold into a HLH-3β structure and therefore, form the four-helix bundle dimerization interface. The inset shows the three short β-sheets at the base of the HLH-3β structure. Reproduced with permission from “M.T. Oliveira, J. Haukka, L.S. Kaguni: Evolution of the metazoan mitochondrial replicase. Genome Biology and Evolution (2015) 7, 943–959”.