Identification of protonated oxygenic ligands of ribonucleotide reductase intermediate X.

ABSTRACT: We previously used a combination of continuous-wave (CW) and pulsed electron-nuclear double resonance (ENDOR) protocols to identify the types of protonated oxygen (OH(x)) species and their disposition within the Fe(III)/Fe(IV) cluster of intermediate X, the direct precursor of the essential diferric-tyrosyl radical cofactor of the beta2 subunit of Escherichia coli ribonucleotide reductase (RNR). We concluded that X contains the [(H(x)O)Fe(III)OFe(IV)] fragment (T model), and does not contain a mu-hydroxo bridge. When combined with a subsequent (17)O ENDOR study of X prepared with H(2)(17)O and with (17)O(2), the results led us to suggest that this fragment is the entire inorganic core of X. This has been questioned by recent reports, but these reports do not themselves agree on the core of

SUBMITTER: Shanmugam M 

PROVIDER: S-EPMC2789976 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature