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Reflections on 25 years in nuclear magnetic resonance spectroscopy of metal ions and metalloproteins
(H) Spectroscopic/Physical Methods
*Convener, J. Peisach
HO(-jl
REFLECTIONS ON 2.5 YEARS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY OF METAL IONS AND METALLOPRO’IEINS. p. Wiithrich, Institut fiir Molekularbiologie und Biophysik, ETH-Hijnggerberg, 8093 Ziirich, Switzerland. Nuclear magnetic resonance spectroscopy (NMR) is presently the only experimental technique besides single crystal diffraction studies that can be employed for the determination of three-dimensional protein structures at atomic resolution [l]. The structures that have so far been solved using NMR include also several metalloproteins, for example, metallothionein. Moreover, during the past 20 years metalloproteins, and in particular hemoproteins, had a pivotal role in the development of the NMR method for protein structure determination. The first part of this lecture will review some of these key experiments, which were started in collaboration with Dr. W.E. Blumberg and other old friends present at this symposium, and the second part will be devoted to a description of a recently determined metalloprotein structure. [l] K. Wiithrich, NMR of Proteins and Nucleic Acids, Wiley, New York (1986).
HO02
THE UTILITY OF EPR IN THE CHARACTERIZATION OF LOW-SPIN HEME PROTEINS. Graham Palmer. Dept of Biochemistry, Rice University, PO Box 1892, Houston, TX 7725 1, USA. In their pioneering work originating in the early seventies Blumberg and Peisach showed how it was possible to analyze the powder epr spectrum of low-spin ferric hemeproteins to infer the identity of the amino acids providing the axial coordination to the heme. It has now become clear that the straightforward application of the method is restricted to heme centers that suffer a substantial rhombic component in their ligand field; this usually results in a low-field g-value smaller than 3.1. However many interesting lowspin heme centers posses g-values in the range 3. I to 3.8, most simply interpreted as due to a much higher symmetry in the ligand field. For these proteins it appears that additional spectroscopic data is needed. Near infrared magnetic circular dichroism, nuclear magnetic resonance and resonance Raman measurements would appear to be helpful in this quest. *In honor of W. E. Blumberg
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*Convener, J. Peisach
HO(-jl
REFLECTIONS ON 2.5 YEARS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY OF METAL IONS AND METALLOPRO’IEINS. p. Wiithrich, Institut fiir Molekularbiologie und Biophysik, ETH-Hijnggerberg, 8093 Ziirich, Switzerland. Nuclear magnetic resonance spectroscopy (NMR) is presently the only experimental technique besides single crystal diffraction studies that can be employed for the determination of three-dimensional protein structures at atomic resolution [l]. The structures that have so far been solved using NMR include also several metalloproteins, for example, metallothionein. Moreover, during the past 20 years metalloproteins, and in particular hemoproteins, had a pivotal role in the development of the NMR method for protein structure determination. The first part of this lecture will review some of these key experiments, which were started in collaboration with Dr. W.E. Blumberg and other old friends present at this symposium, and the second part will be devoted to a description of a recently determined metalloprotein structure. [l] K. Wiithrich, NMR of Proteins and Nucleic Acids, Wiley, New York (1986).
HO02
THE UTILITY OF EPR IN THE CHARACTERIZATION OF LOW-SPIN HEME PROTEINS. Graham Palmer. Dept of Biochemistry, Rice University, PO Box 1892, Houston, TX 7725 1, USA. In their pioneering work originating in the early seventies Blumberg and Peisach showed how it was possible to analyze the powder epr spectrum of low-spin ferric hemeproteins to infer the identity of the amino acids providing the axial coordination to the heme. It has now become clear that the straightforward application of the method is restricted to heme centers that suffer a substantial rhombic component in their ligand field; this usually results in a low-field g-value smaller than 3.1. However many interesting lowspin heme centers posses g-values in the range 3. I to 3.8, most simply interpreted as due to a much higher symmetry in the ligand field. For these proteins it appears that additional spectroscopic data is needed. Near infrared magnetic circular dichroism, nuclear magnetic resonance and resonance Raman measurements would appear to be helpful in this quest. *In honor of W. E. Blumberg
241