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Formate binding to ferric wild type and mutant myoglobins thermodynamic and X‐ray crystallographic study
Author(s) -
Leci Edlira,
Brancaccio Andrea,
Cutruzzolà Francesca,
Allocatelli Carlo Travaglini,
Tarricone Cataldo,
Bolognesi Martino,
Desideri Alessandro,
Ascenzi Paolo
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01324-t
Subject(s) - formate , chemistry , heme , formate dehydrogenase , ligand (biochemistry) , crystallography , ferric , myoglobin , hemeprotein , stereochemistry , inorganic chemistry , biochemistry , receptor , enzyme , catalysis
The X‐ray crystal structure of the formate derivative of ferric loggerhead sea turtle ( Caretta caretta ) Mb has been determined at 2.0 Å resolution ( R = 0.164) by difference Fourier techniques. Formate, sitting in the central part of the heme distal site, is coordinated to the heme iron as unidentate ligand, through the O1 oxygen atom, and is hydrogen bonded to the distal His 64 (E7) NE2 atom through O2. Thermodynamics for formate binding to ferric loggerhead sea turtle Mb, sperm whale Mb, Aplysia limacina Mb, as well as to the VR and VRS mutants of sperm whale Mb were obtained between pH 4.5 and 8.5, at 20.0°C. These results, representing the first structure of a ferric hemoprotein:formate complex solved by X‐ray crystallography, outline the role of amino acid residues at positions E7, F8 and E10 in modulating ligand binding properties of oxygen carrying proteins.