0000000000887280
AUTHOR
E. N. Frolov
Hemoglobin dynamics in rat erythrocytes investigated by M�ssbauer spectroscopy
Rats have been enriched in 57Fe and erythrocytes were isolated from the blood. Mössbauer absorption spectroscopy on the hemoglobin of these erythrocytes has shown rather similar dynamics as found earlier in crystals of myoglobin, in frozen solutions of human hemoglobin and in a number of other proteins. The results strongly indicate that the motion of the heme and presumably some part of the F-helix is mainly influenced by the average viscosity of the sample determined by a network of hydrogen bridges and other weak interactions. Extrapolations of Mössbauer results from protein crystals to proteins in their physiological surroundings seem to be suitable for heme proteins.
Mössbauer Spectroscopy on Photosynthetic Bacteria: Investigation of Reaction Centers of Rhodopseudomonas Viridis
Crystals of 57Fe enriched reaction centers have been investigated by Mossbauer spectroscopy. The cytochrome irons are in the low spin ferric state. The non-heme iron of the electron accepting side is partly ferrous high spin and partly ferrous low spin (or ferric high spin). Under the conditions of the experiment sodium ascorbate reduces only one cytochrome iron into the ferrous low spin state. Membrane bound proteins become flexible at higher temperatures than proteins with a hydrophilic surface. They are also less flexible, at least up to temperatures of about 250 K.