title: Influence of protein dynamics on the metal-sites of ovotransferrin.
abstract: Using the perturbed angular correlations (PAC) technique, the formation of hafnium-ovotransferrin complexes has been studied. Two binding configurations at each of the two specific binding-sites of the protein have been observed. They are characterized by well-defined electric quadrupole frequencies. Information about the dynamics of the protein was derived from temperature dependent measurements of the relaxation constant. The well-resolved spectra taken with fast BaF2-detectors allow a precise determination of the relaxation behaviour of the protein. The results are compared with the predictions from a hydrodynamic model for the reorientation of macromolecules. Thus the hydrodynamic volume of ovotransferrin and its N-terminal half-molecule were determined. The ovotransferrin volume is in agreement with a value derived for human serum transferrin from small angle neutron scattering. From experiments with immobilized protein material there is evidence for internal protein dynamics which is probed by the Hf-ion bound to the specific metal-sites.
authors.affiliation: Institut für Experimentelle Kernphysik, Universität Karlsruhe, Federal Republic of Germany.
authors.forename: F J
authors.initials: FJ
authors.lastname: Schwab
authors.forename: H
authors.initials: H
authors.lastname: Appel
authors.forename: M
authors.initials: M
authors.lastname: Neu
authors.forename: W G
authors.initials: WG
authors.lastname: Thies
mesh_terms: D000818:Animals; D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D002645:Chickens; D003207:Conalbumin / Q000737:chemistry*; D006195:Hafnium; D006863:Hydrogen-Ion Concentration; D008670:Metals; D008956:Models, Chemical; D011487:Protein Conformation; D015204:Spectroscopy, Mossbauer; D013816:Thermodynamics
chemical_list: D008670:Metals; D003207:Conalbumin; D006195:Hafnium