• Neto, Mario De O.
• Kadowaki, Marco A.
• Polikarpov, Igor
• Camilo, Cesar M.
• Pellegrini, Vanessa O. A.
• Araujo, Evandro A. De
• Prates, Érica T.
• Silveira, Rodrigo L.
• Liberato, Marcelo V.
• Popov, Alexander
• Skaf, Munir S.

Abstract

<jats:title>Abstract</jats:title><jats:p>Glycoside hydrolases (GHs) play fundamental roles in the decomposition of lignocellulosic biomaterials. Here, we report the full-length structure of a cellulase from <jats:italic>Bacillus licheniformis</jats:italic> (<jats:italic>Bl</jats:italic>Cel5B), a member of the GH5 subfamily 4 that is entirely dependent on its two ancillary modules (Ig-like module and CBM46) for catalytic activity. Using X-ray crystallography, small-angle X-ray scattering and molecular dynamics simulations, we propose that the C-terminal CBM46 caps the distal N-terminal catalytic domain (CD) to establish a fully functional active site via a combination of large-scale multidomain conformational selection and induced-fit mechanisms. The Ig-like module is pivoting the packing and unpacking motions of CBM46 relative to CD in the assembly of the binding subsite. This is the first example of a multidomain GH relying on large amplitude motions of the CBM46 for assembly of the catalytically competent form of the enzyme.</jats:p>

Topics

• impedance spectroscopy
• simulation
• molecular dynamics
• biomaterials
• decomposition
• X-ray scattering