title: Solution structure of human zeta-COP: direct evidences for structural similarity between COP I and clathrin-adaptor coats.
abstract: COP-I-coated vesicles are protein and lipid carriers that mediate intra-Golgi transport and transport from the cis-Golgi complex to the endoplasmic reticulum in cells. The coatomer of the vesicles coat is comprised of seven subunits: alpha-COP, epsilon-COP, beta'-COP, beta-COP, gamma-COP, delta-COP, and zeta-COP. Here we report the solution structure of a truncated form (residues 1-149; zeta-COP149) of human zeta-COP (total 177 residues). It is the first three-dimensional structure of a "core" subunit of the COP I F-subcomplex. The structure of zeta-COP149 mainly consists of a disordered N-terminal tail, a five-stranded antiparallel beta-sheet, a two-stranded antiparallel beta-sheet, and five alpha-helices. The global folding of zeta-COP149 is very similar to the crystal structures of AP1-sigma1 and AP2-sigma2, directly demonstrating the structural similarity between the "core" subunits of the COP I F-subcomplex and adaptor protein complexes. Through structural comparison and mutagenesis study, we have also demonstrated that the heterodimers of zeta-COP149 and gamma-COP have packing interfaces and relative subunit orientations similar to those of AP2-sigma2 and AP2-alpha heterodimers. These results provide direct evidence supporting the previous proposal that the COP I F-subcomplex and adaptor protein complexes have similar tertiary and quaternary structures.
authors.affiliation: Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing 100871, China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Yu
authors.forename: Jian
authors.initials: J
authors.lastname: Lin
authors.forename: Changwen
authors.initials: C
authors.lastname: Jin
authors.forename: Bin
authors.initials: B
authors.lastname: Xia
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000737:chemistry / Q000378:metabolism; D033962:Adaptor Protein Complex 2 / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D022163:Clathrin-Coated Vesicles / Q000737:chemistry* / Q000378:metabolism; D020756:Coatomer Protein / Q000737:chemistry* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011485:Protein Binding; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012996:Solutions; D040681:Structural Homology, Protein; D020798:Two-Hybrid System Techniques
chemical_list: D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D020756:Coatomer Protein; D012996:Solutions