TY - JOUR
T1 - X-ray crystal structure of the fluoride derivative of Aplysia limacina ferric myoglobin at 2·0 Å resolution. Stabilization of the fluoride ion by hydrogen bonding to Arg66 (E10)
AU - Bolognesi, Martino
AU - Coda, Alessandro
AU - Frigerio, Francesco
AU - Gatti, Giuseppina
AU - Ascenzi, Paolo
AU - Brunori, Maurizio
PY - 1990/6/20
Y1 - 1990/6/20
N2 - The X-ray crystal structure of the fluoride derivative of Aplysia limacina ferric myoglobin has been solved and refined at 2·0 Å resolution; the crystallographic R-factor is 13·6%. The fluoride ion binds to the sixth co-ordination position of the heme iron, 2·2 Å from the metal. Binding of the negatively charged ligand on the distal side of the heme pocket of this myoglobin, which lacks the distal His, is associated with a network of hydrogen bonds that includes the fluoride ion, the residue Arg66 (E10), the heme propionate III, three ordered water molecules and backbone or side-chain atoms from the CD region. A comparison of fluoride and oxygen dissociation rate constants of A. limacina myoglobin, sperm whale (Physeter catodon) myoglobin and Glycera dibranchiata monomeric hemoglobin, suggests that the conformational readjustment of Arg66 (E10) in A. limacina myoglobin may represent the molecular basis for ligand stabilization, in the absence of a hydrogen-bond donor residue at the distal E7 position.
AB - The X-ray crystal structure of the fluoride derivative of Aplysia limacina ferric myoglobin has been solved and refined at 2·0 Å resolution; the crystallographic R-factor is 13·6%. The fluoride ion binds to the sixth co-ordination position of the heme iron, 2·2 Å from the metal. Binding of the negatively charged ligand on the distal side of the heme pocket of this myoglobin, which lacks the distal His, is associated with a network of hydrogen bonds that includes the fluoride ion, the residue Arg66 (E10), the heme propionate III, three ordered water molecules and backbone or side-chain atoms from the CD region. A comparison of fluoride and oxygen dissociation rate constants of A. limacina myoglobin, sperm whale (Physeter catodon) myoglobin and Glycera dibranchiata monomeric hemoglobin, suggests that the conformational readjustment of Arg66 (E10) in A. limacina myoglobin may represent the molecular basis for ligand stabilization, in the absence of a hydrogen-bond donor residue at the distal E7 position.
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U2 - 10.1016/S0022-2836(05)80249-9
DO - 10.1016/S0022-2836(05)80249-9
M3 - Article
C2 - 2359116
AN - SCOPUS:0025292354
VL - 213
SP - 621
EP - 625
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 4
ER -