Journal
JOURNAL OF MAGNETIC RESONANCE
Volume 231, Issue -, Pages 15-21Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jmr.2013.03.004
Keywords
HALS heme centers; Type I heme centers; Large g(max); ESE; Pulsed EPR; Transient nutation
Funding
- NSF [BIR-9224431, DBI-9604939, DBI-0139459]
- NIH [RR020959, DK 31038]
Ask authors/readers for more resources
Continuous wave (CW) electron paramagnetic resonance (EPR) spectroscopy of highly-anisotropic low spin (HALS) ferric heme centers in frozen solutions is not a very informative approach because usually only one feature is reliably observed in the spectra, that at the maximal principal g-value of, typically, 3.3-3.79. The other two EPR turning points are severely broadened by g-strain and are not easily observed in the first-derivative CW EPR spectra. In this work, we have explored the potential of alternative EPR techniques, the electron spin echo (ESE) field sweep and electron spin transient nutation (TN), for obtaining information about the g-tensors of such systems, using as an example a typical HALS ferric heme center, [Fe-III(N-15-coproporphyrin)(CN)(2)]. The analysis of the experimental g-tensor of [Fe-III(N-15-coproporphyrin)(CN)(2)](-) has shown that the widths of the underlying energy distributions for this HALS center are comparable to those found for the rhombic bis-imidazole complex. The greater effect on the g-value distributions for HALS centers is determined by near degeneracy of two of the three lower-energy d-orbitals, d(yz) and d(xz), which contain the unpaired electron. (C) 2013 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available