We have obtained the 470 MHz 19F NMR spectra of wild type [4-F]Trp- labeled myoglobins (MbCO, MbO2, deoxyMb, metMb, and MbCN) and hemoglobins (HbCO, HbO2, and deoxyHb), as well as those of several mutants (W7F Mb, βW 15F Hb, βW37S Hb, and βY 130F Hb, all as the carbonmonoxy adducts), prepared via site-directed mutagenesis. The maximum observed chemical shift range induced by folding is 6.4 ppm. Using a multipole shielding polarizability-local reaction field approach, we have computed the electrostatic field contributions to the fluorine shielding. For residues which do not have F atoms in contact with neighboring groups, we find an ~1 ppm mean square deviation in shift from experiment, with the R2-like structure of HbCOA being in very close accord with experiment.
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