High-resolution structure of human cytoglobin: identification of extra N- and C-termini and a new dimerization mode.
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.
Makino
Masatomo
M
Biometal Science Laboratory, Harima Institute, RIKEN SPring-8 Center, Harima Institute, Japan.
Sugimoto
Hiroshi
H
Sawai
Hitomi
H
Kawada
Norifumi
N
Yoshizato
Katsutoshi
K
Shiro
Yoshitsugu
Y
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
C000627265:CYGB protein, human; D000078842:Cytoglobin; D006418:Heme; D005914:Globins