Figure 1

Inactivated derivatives of B-family DNA polymerases in archaea: inactivation of the principal catalytic motif and phylogeny. The right part of the figure shows the sequences of the essential Mg2+-binding motif of B-family DNA polymerases for two families of active archaeal polymerase (top and middle) and the inactivated derivative (bottom). The motifs are shown in the form of sequence LOGOs where the height of the amino acid symbols is a function of the frequency of the given amino acid in the given position [20, 21]. The left part of the figure shows a phylogenetic tree for archaeal B-family DNA polymerases. Color code: purple, Euryarchaeota (E); green: Crenarchaeota (C); brown: organisms that might represent distinct arcaheal phyla: Nanoarchaeota (N), Korarchaeota (K), and Thaumoarchaeota (T); black, bacteria (B). Each organism is denoted by the full systematic name and the Gene Identifier (GI) number. Multiple sequence alignment of archaeal B-family polymerases (Additional File 1) was constructed using the MUSCLE program [22]. The tree was built using the maximum likelihood method implemented in the MOLPHY program [23] by local rearrangement of an original Fitch tree [24]. The same program was used to compute bootstrap values which are indicated (%) for selected major branches.