using X-ray absorption near edge structure (XANES) spectroscopy, we show that under prolonged exposure to Synchrotron X-rays, at T < 10 K, the Fe-heme in carbonmonoxy-myoglobin (MbCO) undergoes a slow two-state transition process. The final spectrum is nearly identical to that of the classical photoproduct (Mb*CO) obtained by UV-visible light illumination at 15 K. By increasing the temperature, the starting spectrum of MbCO is recovered at T > 100 K, demonstrating that the process is reversible and no damage occurred at the heme site in the time course of the experiment. Thus, the overall X-ray-induced process at low temperature is identical to the well-known (light-induced) photolysis of CO-hemeproteins.

X-Ray-Induced Lysis of the Fe-O Bond in Carbonmonoxy-Myoglobin

DELLA LONGA, STEFANO;
2010

Abstract

using X-ray absorption near edge structure (XANES) spectroscopy, we show that under prolonged exposure to Synchrotron X-rays, at T < 10 K, the Fe-heme in carbonmonoxy-myoglobin (MbCO) undergoes a slow two-state transition process. The final spectrum is nearly identical to that of the classical photoproduct (Mb*CO) obtained by UV-visible light illumination at 15 K. By increasing the temperature, the starting spectrum of MbCO is recovered at T > 100 K, demonstrating that the process is reversible and no damage occurred at the heme site in the time course of the experiment. Thus, the overall X-ray-induced process at low temperature is identical to the well-known (light-induced) photolysis of CO-hemeproteins.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11697/16412
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