01840nas a2200313 4500008004500000020001400045245009000059210006900149260000800218300000600226490000700232520100400239653001501243653001201258653001701270653000801287653001301295653002801308653001001336653001201346653002401358653001701382653001001399100001701409700001701426700001401443700002001457856004901477 2005 Engldsh a1539-375500aLarge oxidation dependence observed in terahertz dielectric response for cytochrome c0 aLarge oxidation dependence observed in terahertz dielectric resp cOct a40 v723 a
Far infrared dielectric response is used to characterize the collective mode density of states for cytochrome c as a function of oxidation state and hydration using terahertz time domain spectroscopy. A strong absorbance and refractive index increase was observed with the oxidation. A simple phenomenological fitting using a continuous distribution of oscillators reproduces the frequency dependence of the complex dielectric response as well as demonstrates quantitative agreement with a uniform increase in either mode density or polarizability with oxidation in the 5-80 cm(-1) frequency range. Hydration dependence measurements find that a difference in the equilibrium water content for ferri and ferro cytochrome c is not sufficient to account for the large change in terahertz response. The large dielectric increase at terahertz frequencies with oxidation suggests either a significant global softening of the potential and/or a significant increase in polarizability with oxidation.
10aabsorption10abinding10aconformation10adna10adynamics10aheart ferricytochrome-c10amodes10aPhysics10aprotein flexibility10aspectroscopy10astate1 aChen, J., Y.1 aKnab, J., R.1 aCerne, J.1 aMarkelz, A., G. uhttps://markelz.physics.buffalo.edu/node/263