We have performed Fe K-edge X-ray absorption spectroscopy measurements at BM08 of the ESRF synchrotron in Grenoble in two extensively studied soluble heme proteins (MbCO and cyt c) and in a membrane pigment-protein mplex (bacterial photosynthetic reaction center) in solution as well as in trehalose matrices. The aim was to investigate possible matrix induced structural alterations. Changes between solution and trehalose have been detected in all proteins. Interestingly, the effect of low temperature on the EXAFS signal in solution is much smaller than that induced by the trehalose matrix. This indicates that trehalose alters dramatically the protein energy landscape, probably hindering the dynamics and promoting only some conformational substates.
Matrix effect on the local structure of Fe in myoglobin, cytochrome c and photosynthetic reaction center. SC-1696.
VENTUROLI, GIOVANNI;BOSCHERINI, FEDERICO;GIACHINI, LISA;FRANCIA, FRANCESCO;
2005
Abstract
We have performed Fe K-edge X-ray absorption spectroscopy measurements at BM08 of the ESRF synchrotron in Grenoble in two extensively studied soluble heme proteins (MbCO and cyt c) and in a membrane pigment-protein mplex (bacterial photosynthetic reaction center) in solution as well as in trehalose matrices. The aim was to investigate possible matrix induced structural alterations. Changes between solution and trehalose have been detected in all proteins. Interestingly, the effect of low temperature on the EXAFS signal in solution is much smaller than that induced by the trehalose matrix. This indicates that trehalose alters dramatically the protein energy landscape, probably hindering the dynamics and promoting only some conformational substates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
