
TY  - JOUR
A1  - Trewhella, J 
A1  - Appleby, CA 
A1  - Wright, PE 
T1  - <sup>1</sup>H N.M.R Studies of High-Spin Complexes of Soybean Leghemoglobin. Interactions Between the Distal Histidine and Acetate, Formate and Fluoride Ligands
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1986
VL  - 39
IS  - 2
SP  - 317
EP  - 324
KW  - 
UR  - https://doi.org/10.1071/CH9860317 
N2  - High-resolution 1H n.m.r . spectra have been measured for the acetate, formate and fluoride complexes of ferric soybean leghaemoglobin a. The chemical shifts of the resolved ow-field haem resonances are very sensitive to pH, reflecting titration of a group, assigned as the distal histidine, with pKa 7.1, 7.3 and 6.2 for the acetate, formate and fluoride complexes respectively. The magnitude of the pH-induced resonance shifts indicates direct interaction between the distal histidine and the axial ligand . The hyperfine shifted resonances of ferrous deoxyleghaemoglobin, in which no sixth ligand is expected, are insensitive to pH over the range pH 5.5-9.3. Evidence for conformational mobility of the distal histidine is presented. 
ER  -

