Sandbox GGC15

DNA TOPOISOMERASE I

spinqualitylabelsall models Caption for this structure Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Eukaryotic DNA topoisomerase I (topo I) is a protein that reduces the strain from the supercoils that are caused during transcription and translation. There are two types of topoisomerases. Type 1 topoisomerases are monomeric and break one strand of DNA. Type 2 topoisomerases are dimeric, meaning that they made up of two units and break both strands of the DNA helix. They are able to pass another part of the duplex through the cut, and close the cut using ATP. Structure Human topo 1 is composed of 765 amino acids . The enzyme consist of 4 regions which are the NH2-terminal, core, linker, and COOH-terminal domains. The NH2-terminal is approximately 210 residues long, it is highly charged, disordered, and contains few hydrophobic amino acids. The COOH-terminal domain is made up of residues 713 to 765 and contains the important amino aside Tyrosine 223. The location of the active site is at this amino acid. Active Site Topo1 reduces stress in DNA by causing breaks in the DNA helix The active site is catalytic and forms a phosphoester bond with the 3' phosphate at the site of cleavage on the DNA strand. Relevance Many anticancer drugs target topo 1 enzymes. Structural highlights This is a sample scene created with SAT to color by Group, and another to make a transparent representation of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.