Structure and function of human hemoglobin covalently labeled with periodate-oxidized adenosine triphosphate.
Periodate-oxidized adenosine triphosphate (o-ATP), a ribose ring-opened dialdehyde derivative of ATP, reacts specifically with human deoxyhemoglobin to give a single major covalently modified product after reduction with sodium borohydride. This product, designated di-ATP Hb, was isolated using ion-exchange chromatography and shown to have incorporated two molecules of o-ATP/tetramer. Peptide mapping and x-ray crystallography at 2.8-A resolution indicate that a covalent adduct is formed between the ligand and residues Lys-82 EF6 of each beta chain in the organic phosphate-binding site of the molecule. di-ATP Hb exhibits a significantly decreased oxygen affinity (P50 = 20.8 mm Hg versus 5.8 mm Hg control; 50 mM 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-propane-1,3-diol, pH 7.4, 0.1 M C, 20 degrees C). The subunit cooper-activity of di-ATP Hb is also reduced (nmax = 1.9 versus 2.7 control).
Kavanaugh
M P
MP
Department of Biochemistry, Oregon Health Sciences University, Portland 97201.
Perutz
M F
MF
Fermi
G
G
Shih
D T
DT
Jones
R T
RT
D000255:Adenosine Triphosphate / Q000378:metabolism*; D001894:Borohydrides; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006441:Hemoglobin A / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010446:Peptide Fragments; D010504:Periodic Acid; D014357:Trypsin; D014961:X-Ray Diffraction
D001894:Borohydrides; D006454:Hemoglobins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D010504:Periodic Acid; C025364:sodium borohydride; D000255:Adenosine Triphosphate; C100003:deoxyhemoglobin; D006441:Hemoglobin A; C009288:metaperiodate; D014357:Trypsin; D010100:Oxygen