Full-length structural model of RET3 and SEC21 in COPI: Identification of binding sites on the appendage for accessory protein recruitment motifs

Abstract

COPI, a 600 kD heptameric complex (consisting of subunits α, β, γ, θ, ε, ζ, and β') "gcoatomer", h assembles non-clathrin-coated vesicles and is responsible for intra-Golgi and Golgi-to-ER protein trafficking. Here, we report the three-dimensional structures of the entire sequences of yeast Sec21 (γ-COPI mammalian ortholog), yeast Ret3 (ζ-COPI mammalian ortholog), and the results of successive molecular dynamics investigations of the subunits and assembly based on a protein.protein docking experiment. The three-dimensional structures of the subunits in complexes indicate the residues of the two subunits that impact on assembly, the conformations of Ret3 and Sec21, and their binding orientati..