Study of the rhizobacterium Azospirillum brasilense Sp245 using Mِssbauer spectroscopy with a high velocity resolution: Implication for the analysis of ferritin-like iron cores

The results of a comparative study of two samples of the rhizobacterium Azospirillum brasilense (strain Sp245) prepared in different conditions and of human liver ferritin using Mِssbauer spectroscopy with a high velocity resolution demonstrated the presence of ferritin-like iron (i.e. iron similar to that found in ferritin-like proteins) in the bacterium. Mِssbauer spectra of these samples were fitted in two ways: as a rough approximation using a one quadrupole doublet fit (the homogeneous iron core model) and using a superposition of quadrupole doublets (the heterogeneous iron core model). Both results demonstrated differences in the Mِssbauer parameters for mammalian ferritin and for bacterial ferritin-like iron. Moreover, some differences in the Mِssbauer parameters were observed between the two samples of A. brasilense Sp245 related to the differences in their preparation conditions.