Skip to main content
. 2016 Feb 22;44(6):2795–2805. doi: 10.1093/nar/gkw097

Figure 3.

Figure 3.

Conserved domains and catalytic residues of Thaumarcheal TopIB. (A) Domain organization of human Top1 (Hs-Top1) and Cs-TopIB. In purple the non-conserved eukaryotic N-terminal domain, in green the conserved Core domain, in red the Linker domain, in blue the C-terminal domain with the catalytic tyrosine and in light green a small Cs-TopIB additional C-terminal domain. (B) Multiple amino-acid sequence alignments of topoisomerase IB in proximity of the active site. Amino acids in the active site (R488, K532, R590, H632, Y723) are marked with a + and their numbering is based on the human protein. The aligned sequences are from Candidatus Caldiarchaeum subterraneum (C.sub), Cenarchaeum symbiosum (C.sym), Nitrosopumilus maritimus (N.m), Nitrososphaera viennensis (N.v), Homo sapiens (H.s), Mus musculus (M.m) and Arabidopsis thaliana (A.t). Residues conserved in all sequences are highlighted in yellow. The tyrosine 477 of Ca. C. subterraneum mutated to a phenylalanine corresponds to Y723 of the human protein. (C) Ribbon representation of the crystal structure of the human Top1 in yellow (PDB ID: 1K4T) and the Cs-TopIB molecular model in blue. Camptothecin (CPT) and catalytic tyrosine are rainbow colored.