Electron spin echo envelope modulation studies of the Cu(II)-substituted derivative of isopenicillin N synthase: A structural and spectroscopic model
- Yeshiva Univ., Bronx, NY (United States)
- Univ. of Minnesota, Minneapolis (United States)
- Lilly Research Labs., Indianapolis, IN (United States)
Electron spin echo envelope modulation spectroscopy (ESEEM) was used to study the active site structure of isopenicillin N synthase (IPNS) from Cephalosporium acremonium with Cu(II) as a spectroscopic probe. Fourier transform of the simulated electron spin-echo envelope for the Cu(II)-substituted enzyme, Cu(II)IPNS, revealed two nearly magnetically equivalent, equatorially coordinated His imidazoles. The superhyperfine coupling constant, A{sub iso}, for the remote {sup 14}N of each imidazole was 1.65 MHz. The binding of substrate to the enzyme altered the magnetic coupling so that A{sub iso} is 1.30 MHz for one nitrogen and 2.16 MHz for the other. From a comparison of the ESSEM of Cu(II)IPNS in D{sub 2}O and H{sub 2}O, it is suggested that water is a ligand of Cu(II) and this is displaced upon the addition of substrate.
- OSTI ID:
- 5487358
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:48; ISSN 0006-2960; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
COPPER COMPOUNDS
DRUGS
ELECTRON SPIN RESONANCE
ENZYMES
FOURIER ANALYSIS
HEAVY WATER
HYDROGEN COMPOUNDS
HYPERFINE STRUCTURE
ISOTOPES
LIGASES
LIGHT NUCLEI
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
NITROGEN 14
NITROGEN ISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PENICILLIN
PROTEINS
RESONANCE
SPIN ECHO
STABLE ISOTOPES
SUBSTRATES
TRANSITION ELEMENT COMPOUNDS
WATER