TY - JOUR
T1 - Mapping protein matrix cavities in human cytoglobin through Xe atom binding
AU - De Sanctis, Daniele
AU - Dewilde, Sylvia
AU - Pesce, Alessandra
AU - Moens, Luc
AU - Ascenzi, Paolo
AU - Hankeln, Thomas
AU - Burmester, Thorsten
AU - Bolognesi, Martino
PY - 2004/4/16
Y1 - 2004/4/16
N2 - Cytoglobin is the fourth recognized globin type, almost ubiquitously distributed in human tissues; its function is still poorly understood. Cytoglobin displays a core region of about 150 residues, structurally related to hemoglobin and myoglobin, and two extra segments, about 20 residues each, at the N- and C-termini. The core region hosts a large apolar cavity, held to provide a ligand diffusion pathway to/from the heme, and/or ligand temporary docking sites. Here we report the crystal structure (2.4Å resolution, R-factor 19.1%) of a human cytoglobin mutant bearing the CysB2(38)→Ser and CysE9(83)→Ser substitutions (CYGB*), treated under pressurized xenon. Three Xe atoms bind to the heme distal site region of CYGB* mapping the protein matrix apolar cavity. Despite the conserved globin fold, the cavity found in CYGB* is structured differently from those recognized to play a functional role in myoglobin, neuroglobin, truncated hemoglobins, and Cerebratulus lacteus mini-hemoglobin.
AB - Cytoglobin is the fourth recognized globin type, almost ubiquitously distributed in human tissues; its function is still poorly understood. Cytoglobin displays a core region of about 150 residues, structurally related to hemoglobin and myoglobin, and two extra segments, about 20 residues each, at the N- and C-termini. The core region hosts a large apolar cavity, held to provide a ligand diffusion pathway to/from the heme, and/or ligand temporary docking sites. Here we report the crystal structure (2.4Å resolution, R-factor 19.1%) of a human cytoglobin mutant bearing the CysB2(38)→Ser and CysE9(83)→Ser substitutions (CYGB*), treated under pressurized xenon. Three Xe atoms bind to the heme distal site region of CYGB* mapping the protein matrix apolar cavity. Despite the conserved globin fold, the cavity found in CYGB* is structured differently from those recognized to play a functional role in myoglobin, neuroglobin, truncated hemoglobins, and Cerebratulus lacteus mini-hemoglobin.
KW - Heme ligand diffusion
KW - Human cytoglobin
KW - Protein matrix cavities/tunnels
KW - X-ray crystallography
KW - Xe binding
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U2 - 10.1016/j.bbrc.2004.03.007
DO - 10.1016/j.bbrc.2004.03.007
M3 - Article
C2 - 15044115
AN - SCOPUS:1642377942
VL - 316
SP - 1217
EP - 1221
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -