Domain mobility as probed by small-angle X-ray scattering may account for substrate access to the active site of two copper-dependent amine oxidases

Dainese E;Sabatucci A;PINTUS, FRANCESCA;MEDDA, ROSARIA;Angelucci CB;Floris G;Maccarrone M.

2014-01-01

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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.