Domain mobility as probed by small-angle X-ray scattering may account for substrate access to the active site of two
Enrico Dainese1, Annalaura Sabatucci1, Francesca Pintus2
1Faculty of Bioscience and Technology for Food Agriculture and Environment, University of Teramo, Teramo, Italy.
Abstract:
Amine oxidases are a family of dimeric enzymes that contain one copper(II) ion and one 2,4,5-trihydroxyphenyalanine quinone per subunit. Here, the low-resolution structures of two Cu/TPQ amine oxidases from lentil (Lens esculenta) seedlings and from Euphorbia characias latex have been determined in solution by small-angle X-ray scattering. The active site of these enzymes is highly buried and requires a conformational change to allow substrate access. The study suggests that the funnel-shaped cavity located between the D3 and D4 domains is narrower within the crystal structure, whereas in solution the D3 domain could undergo movement resulting in a protein conformational change that is likely to lead to easier substrate access.
