13C nuclear magnetic resonance study of molecular motions and conformational transitions in muscle calcium binding parvalbumins

13C nuclear magnetic resonance is used to detect the Ca2+ ion controlled conformational transition in muscle calcium binding parvalbumin and to study its intramolecular motions. Nuclear relaxation parameters are used to evaluate the reorientation rates of the protein and some of the amino acid side chains. While peripheral residues exhibit greater motional freedom than the protein interior, an interesting finding is that significant rapid internal motion is present in the phenylalanine rings comprising the hydrophobic core of the protein.     

Fine structure in quenched Fe-Al-C steels

The origin of “extra” spots in electron diffraction patterns taken from retained austenite and martensite in Fe-7 pct Al-2 pct C has been investigated. The present interpretation differs from that of previous investigators. It is concluded that a high density of fine carbide precipitates 50Å in diameter is responsible for the extra reflections. The precipitates have the perovskite structure and grow epitaxially in the austenite during quenching. When martensite forms at a lower temperature, the precipitates are transformedin situ.