Report

A Manganese(IV)/Iron(III) Cofactor in Chlamydia trachomatis Ribonucleotide Reductase

See allHide authors and affiliations

Science  25 May 2007:
Vol. 316, Issue 5828, pp. 1188-1191
DOI: 10.1126/science.1141179

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Abstract

In a conventional class I ribonucleotide reductase (RNR), a diiron(II/II) cofactor in the R2 subunit reacts with oxygen to produce a diiron(III/IV) intermediate, which generates a stable tyrosyl radical (Y⚫). The Y⚫ reversibly oxidizes a cysteine residue in the R1 subunit to a cysteinyl radical (C⚫), which abstracts the 3′-hydrogen of the substrate to initiate its reduction. The RNR from Chlamydia trachomatis lacks the Y⚫, and it had been proposed that the diiron(III/IV) complex in R2 directly generates the C⚫ in R1. By enzyme activity measurements and spectroscopic methods, we show that this RNR actually uses a previously unknown stable manganese(IV)/iron(III) cofactor for radical initiation.

    View Full Text