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Biologische Systeme und Medizin Vortrag: Fr., 11:50–12:10 F-V60
Inelastic Nuclear Resonant Scattering as a Local Probe for the Dynamics
of Iron-Sulfur Proteins
Volker Schünemann 1
1 TU Kaiserslautern, Fachbereich Physik, Erwin-Schrödinger-Str. 56, 67663 Kaiser-
slautern
Iron-sulfur proteins serve mainly as electron transfer proteins but act sometimes also
as oxygen sensors or as enzymes. In both cases the dynamic properties of the ironsulfur
centers are related to protein function. In electron transfer proteins they tune
electron transfer rates. In sensor proteins as well as in iron enzymes dynamic properties
influence the binding of molecules to the active iron site. The dynamic properties
of these iron sites are conventionally studied by vibrational spectroscopy like Infrared
(IR) or Resonance Raman (RR) spectroscopy. Inelastic nuclear resonant scattering
is complementary to these methods because this technique is site selective and does
not rely on optical selection rules. Therefore iron vibrations can also be detected if
IR or RR fails as in the case of reduced rubredoxins which have a single tetrahedral
sulfur coordinated iron site. The applicability of inelastic nuclear resonant scattering
to reduced rubredoxin has been recently shown independently by two groups [1,2]. In
this contribution inelastic nuclear resonant scattering experiments applied to proteins
with more complicated iron sites like the 4Fe-4S site of ferredoxin will be discussed.
These experiments may put the basis for future studies on the dynamics of even more
complex iron sulfur centers like those in hydrogenases, enzymes which are involved in
biological hydrogen production.
[1] Y. Xiao et al., J. Am. Chem. Soc. 127 (2005) 14596.
[2] A.X. Trautwein et al. Hyperfine Interact accepted.