The assignment of the paramagnetically shifted resonances of the Fe(II)-bleomycin complex in D2O has been accomplished using the transfer of saturation method. A number of additional resonances arising from labile NH protons which are shifted by the metal ion are observed in the 1H spectrum of the complex in H2O. The temperature dependence of the chemical shifts is consistent with the formation of an isolated 1:1 complex, but does not obey either the Curie Law or the Curie-Weiss Law. The magnitude of the shifts suggests that the valeric acid hydroxyl (or carbonyl) group, the α-amino group, the imidazole Nπ, the carbamoyl oxygen, the pyrimidine N1 and/or the secondary amino group may be coordinated to the iron(II).
ASJC Scopus subject areas
- Molecular Biology