Marchat [33] detected the same patterns in several eukaryotic orthologs proteins and suggested horizontal gene transfer between bacteria and eukaryotes. DNA helicases from other families As mentioned above, only six of the twelve helicase families are supposed to comprise

RNA helicases (DEAD-box, DEAH-box, Ski2-like, RIG-I-like, NS3/NPH-II and Upf1-like family) and the remaining families consist of DNA helicases. In Giardia we found 14 additional ORFs that could be considered DNA helicases and grouped them into www.selleckchem.com/products/Y-27632.html the three following families: Swi2/Snf2 Selleckchem PHA-848125 family Seven ORFs were linked to this family based on the sequence features and compared with members of this family belonging to other species. They present the eight characteristic motifs, with the sequence conservation being represented in the logos under the alignment (see Additional file 8: Figure S5). This family is one of the largest helicase families in G. lamblia SF2, with an average length of 1,560 amino

acids (Table S2). The N- and C-terminal regions present characteristic domains; almost all of them show one or two SNF2N domains that were described as the ATPase component of the SNF2/SWI multi-subunit complex, disrupting histone-DNA interactions. Other domains found within Bortezomib supplier these ORFs were the SANT domain, the BROMO domain and a CHROMO domain. RecQ family This is the smallest family, with only three members found in the Giardia genome. These helicases also have one of the smallest average lengths, with only the central HCD. The eight characteristic motifs that

defined this family are highly conserved, as shown in Additional file 9: Figure S6. The three ORFs share the greatest homology with the BLM (Bloom syndrome) Dynein gene from humans, which is believed to act by suppressing inappropriate recombination [49]. They are also homolog for the yeast SGS1 gene, a nucleolar DNA helicase of the RecQ family involved in genome integrity [50]. Rad3 family This family is composed of four members in G. lamblia. It presents the largest HCD of all the SF2 helicases due to the presence of a differently large linker region between the DEXDc and the HELICc domains. They present homology in all the eight conserved motifs, except for ORF GL50803_5910, which lacks Motifs Ia and Ib (see Additional file 10: Figure S7). This ORF presents no significant similarity to human proteins; however, it was included in this family based on results of sequence and multiple alignment analyses (see Tree in Additional file 3: Figure S1). The helicase core domain within the dicer sequence The HCD is an important component of higher eukaryotes’ Dicer enzymes, and is involved in some functions regarding the fundamental participation of this protein in RNAi [51–55].