title: High-resolution structure of human cytoglobin: identification of extra N- and C-termini and a new dimerization mode.
abstract: Cytoglobin (Cgb) is a recently discovered member of the vertebrate haem-containing globin family. The structure of a new crystal form of wild-type human Cgb (space group C2) was determined at a resolution of 1.68 Angstrom. The results show the presence of an additional helix in the N-terminal residues (4-20) prior to the A helix and an ordered loop structure in the C-terminal region (168-188), while these extended peptides were invisible owing to disorder in the previously reported structures using a P3(2)21 crystal at a resolution of 2.4 Angstrom. A detailed comparison of the two crystal structures shows differences in the conformation of the residues (i.e. Arg84) in the haem environment owing to a different dimeric arrangement.
authors.affiliation: Biometal Science Laboratory, Harima Institute, RIKEN SPring-8 Center, Harima Institute, Japan.
authors.forename: Masatomo
authors.initials: M
authors.lastname: Makino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sawai
authors.forename: Norifumi
authors.initials: N
authors.lastname: Kawada
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Yoshizato
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Shiro
mesh_terms: D018360:Crystallography, X-Ray; D000078842:Cytoglobin; D019281:Dimerization; D005914:Globins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D006801:Humans; D008958:Models, Molecular; D017433:Protein Structure, Secondary
chemical_list: C000627265:CYGB protein, human; D000078842:Cytoglobin; D006418:Heme; D005914:Globins