Electron spin echo envelope modulation studies of the Cu(II)-substituted derivative of isopenicillin N synthase: A structural and spectroscopic model

Journal Article · Tue Dec 03 00:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00112a010· OSTI ID:5487358

Jiang, Feng; Peisach, J ^[1]; Ming, Lijune; Que, L Jr ^[2]; Chen, V J ^[3]

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1. Yeshiva Univ., Bronx, NY (United States)
2. Univ. of Minnesota, Minneapolis (United States)
3. 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), Vol. 30:48; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
LIGASES
ELECTRON SPIN RESONANCE
COPPER COMPOUNDS
FOURIER ANALYSIS
HEAVY WATER
HYPERFINE STRUCTURE
MOLECULAR STRUCTURE
NITROGEN 14
PENICILLIN
SPIN ECHO
SUBSTRATES
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
DRUGS
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ISOTOPES
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MAGNETIC RESONANCE
NITROGEN ISOTOPES
NUCLEI
ODD-ODD NUCLEI
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OXYGEN COMPOUNDS
PROTEINS
RESONANCE
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
WATER
550601* - Medicine- Unsealed Radionuclides in Diagnostics