A stable Fe{sup III}-Fe{sup IV} replacement of tyrosyl radical in a class I ribonucleotide reductase

Journal Article · Fri May 20 04:00:00 EDT 2005 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/j.bbrc.2005.03.104· OSTI ID:20709197

Voevodskaya, N ^[1]; Lendzian, F ^[2]; Graeslund, A ^[1]

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1. Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm (Sweden)
2. Max-Volmer-Laboratory, Institute for Chemistry, PC14, Technical University Berlin, D-10623 Berlin (Germany)

Ribonucleotide reductase (RNR) of Chlamydia trachomatis is a class I RNR enzyme composed of two homodimeric components, proteins R1 and R2. In class I RNR, R1 has the substrate binding site, whereas R2 has a diferric site and normally in its active form a stable tyrosyl free radical. C. trachomatis RNR is unusual, because its R2 component has a phenylalanine in the place of the radical carrier tyrosine. Replacing the tyrosyl radical, a paramagnetic Fe{sup III}-Fe{sup IV} species (species X, normally a transient intermediate in the process leading to radical formation) may provide the oxidation equivalent needed to start the catalytic process via long range electron transfer from the active site in R1. Here EPR spectroscopy shows that in C. trachomatis RNR, species X can become essentially stable when formed in a complete RNR (R1/R2/substrate) complex, adding further weight to the possible role of this species X in the catalytic reaction.

• OSTI ID: 20709197
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 4 Vol. 330; ISSN 0006-291X; ISSN BBRCA9
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
ENZYMES
OXIDATION
PARAMAGNETISM
PHENYLALANINE
SPECTROSCOPY
SUBSTRATES
TYROSINE