GHファミリー23に属する新奇キチナーゼの構造と機能

抄録

Chitinase C from a moderate thermophilic strain Ralstonia sp. A-471 (Ra-ChiC) is a novel chitinase which has a catalytic domain sequence similar to goose type lysozymes and, unlike other chitinases, Ra-ChiC belongs to glycoside hydrolase family 23. We have determined the crystal structures of Ra-ChiC catalytic domain and its inactive mutant with or without chitin oligosaccharides. These structures indicated that Ra-ChiC has a unique substrate-binding site including a tunnel-shaped cavity. In addition, our mutation analysis showed that not only a highly conserved Glu141 but also Asp226 located at the roof of the tunnel have quite important roles in catalysis.