Hole burning and pressure phenomena in chromoproteins

Abstract We investigated the behavior of spectral holes under pressure at various frequencies within the inhomogeneous band for two proteins, namely myoglobin and horseradish peroxidase. In order to achieve narrow bandwidth hole burning, the heme chromophore was replaced by protoporphyrin IX and mesoporphyrin IX, respectively. In myoglobin, we found that the pressure induced shift of the holes varied in a strongly non-linear fashion, when the burn-frequency was tuned across the absorption band. In horseradish peroxidase the pressure shift was linear with burn-frequency but changed in a dramatic fashion upon complex formation with a substrate molecule. These observations are interpreted with…

An unambiguous procedure for discovering relaxation influence on M�ssbauer spectra

A mathematical procedure which gives an opportunity to distinguish between relaxation and distribution mechanisms of the Mossbauer line broadening is proposed. It is based on the method of Mossbauer line sharpening developed recently [1] and allows one to answer unambiguously the question whether or not relaxation manifests itself in Mossbauer measurements by examining the wings of the spectrum. The procedure is applied to the spectra of high spin ferric metmyoglobin and (Fe0.65Ni0.35)1−xMnx alloys. Analysis of the metmyoglobin spectra manifests the presence of the relaxation influence in the temperature range 10 K≦T≦100 K. Analysis of the alloy spectra shows that for the temperatures 4 K≦T…

Poster contributions