The free radical in pyruvate formate-lyase is located on glycine-734

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.89.3.996· OSTI ID:5617907

Wagner, A F.V.; Frey, M; Knappe, J ^[1]; Neugebauer, F A ^[2]; Schaefer, W ^[3]

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1. Univ. Heidelberg (West Germany)
2. Max-Planck-Inst. fuer Medizinische Forshung, Heidelberg (West Germany)
3. Max-Planck-Inst. fuer Biochemie, Martinsried (West Germany)

Pyruvate formate-lyase from anaerobic Escherichia coli cells converts pyruvate to acetyl-CoA and formate by a unique homolytic mechanism that involves a free radical harbored in the protein structure. By EPR spectroscopy to selectively {sup 13}C-labeled enzyme, the radical has been assigned to carbon-2 of a glycine residue. Estimated hyperfine coupling constants to the central {sup 13}C nucleus and to {sup 13}C nuclei in {alpha} and {beta} positions agree with literature data for glycine radical models. N-coupling was verified through uniform {sup 15}N-labeling. The large {sup 1}H hyperfine splitting (1.5 mT) dominating the EPR spectrum was assigned to the {alpha} proton, which in the enzyme radical is readily solvent-exchangeable. Oxygen destruction of the radical produced two unique fragments (82 and 3 kDa) of the constituent polypeptide chain. The carbon-centered radical is probably resonance-stabilized through the adjacent carboxamide groups in the polypeptide main chain and could be comparable energetically with other known protein radicals carrying the unpaired electron in tyrosine or tryptophan residues.

• OSTI ID: 5617907
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 89:3; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BACTERIA
BARYONS
CARBON 13
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON ISOTOPES
CARBOXYLIC ACIDS
ELECTRON SPECTRA
ELECTRON SPIN RESONANCE
ELEMENTARY PARTICLES
ENZYMES
ESCHERICHIA COLI
EVEN-ODD NUCLEI
FERMIONS
FORMIC ACID
GLYCINE
HADRONS
HYDROXY ACIDS
HYPERFINE STRUCTURE
ISOTOPES
KETO ACIDS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAGNETIC RESONANCE
MICROORGANISMS
MONOCARBOXYLIC ACIDS
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROTEINS
PROTONS
PYRUVIC ACID
RADICALS
RESONANCE
SPECTRA
STABLE ISOTOPES
TRANSFERASES
TYROSINE