Fe vibrational spectroscopy of myoglobin and cytochrome f.
The Fe vibrational density of states (VDOS) has been determined for the heme proteins deoxymyoglobin, metmyoglobin, and cytochrome f in the oxidized and reduced states, using nuclear resonance vibrational spectroscopy (NRVS). For cytochrome f in particular, the NRVS spectrum is compared with multiwavelength resonance Raman spectra to identify those Raman modes with significant Fe displacement. Modes not seen by Raman due to optical selection rules appear in the NRVS spectrum. The mean Fe force constant extracted from the VDOS illustrates how Fe dynamics varies among these four monoheme proteins, and is correlated with oxidation and spin state trends seen in model heme compounds. The protein's contribution to Fe motion is dominant at low frequencies, where coupling to the backbone tightly constrains Fe displacements in cytochrome f, in contrast to enhanced heme flexibility in myoglobin.
Adams
Kristl L
KL
Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA.
Tsoi
Stanislav
S
Yan
Jiusheng
J
Durbin
Stephen M
SM
Ramdas
Anant K
AK
Cramer
William A
WA
Sturhahn
Wolfgang
W
Alp
E Ercan
EE
Schulz
Charles
C
D045348:Cytochromes f / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D011487:Protein Conformation; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D014732:Vibration
D009211:Myoglobin; D045348:Cytochromes f; D007501:Iron