Figure 4
Structural superposition of the ancestral core in pancreatic lipase and patatin. 3D structures of the conserved core module (see Figure 2) from pancreatic lipase 1N8S [27] (A, segments 68–77, 144–166, 170–176), patatin 1OXW [13] (C, segments 28–37, 70–87, 148–158) and a superposition of both (B). The module starts with a β-strand (β-2) that is followed by another β-strand (β-1), an α-helix (α+1) and a β-strand (β+1). Numbers in parentheses indicate the relative positions to the nucleophilic elbow in the protein sequence. This loop is crucial for catalytic activity and typically contains a catalytic serine. It is located between the adjacent secondary structure elements β-1 and α+1. The connections to the other β-strands (β-2 and β+1) are not direct and can include longer stretches of additional secondary structure.