Structure of the high-valent FeIIIFeIV state in ribonucleotide reductase (RNR) of Chlamydia trachomatis--combined EPR, 57Fe-, 1H-ENDOR and X-ray studies.
In: Biochimica et biophysica acta, Jg. 1774 (2007-10-01), Heft 10, S. 1254-63
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Zugriff:
A recently discovered subgroup of class I ribonucleotide reductase (RNR) found in the infectious bacterium Chlamydia trachomatis (C. trachomatis) was shown to exhibit a high-valent Fe(III)Fe(IV) center instead of the tyrosyl radical observed normally in all class I RNRs. The X-ray structure showed that C. trachomatis WT RNR has a phenylalanine at the position of the active tyrosine in Escherichia coli RNR. In this paper the X-ray structure of variant F127Y is presented, where the tyrosine is restored. Using (1)H- and (57)Fe-ENDOR spectroscopy it is shown, that in WT and variants F127Y and Y129F of C. trachomatis RNR, the Fe(III)Fe(IV) center is virtually identical with the short-lived intermediate X observed during the iron oxygen reconstitution reaction in class I RNR from E. coli. The experimental data are consistent with a recent theoretical model for X, proposing two bridging oxo ligands and one terminal water ligand. A surprising extension of the lifetime of the Fe(III)Fe(IV) state in C. trachomatis from a few seconds to several hours at room temperature was observed under catalytic conditions in the presence of substrate. These findings suggest a possible new role for the Fe(III)Fe(IV) state also in other class I RNR, during the catalytic radical transfer reaction, by which the substrate turnover is started.
Titel: |
Structure of the high-valent FeIIIFeIV state in ribonucleotide reductase (RNR) of Chlamydia trachomatis--combined EPR, 57Fe-, 1H-ENDOR and X-ray studies.
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Autor/in / Beteiligte Person: | Voevodskaya, N ; Galander, M ; Högbom, M ; Stenmark, P ; McClarty, G ; Gräslund, A ; Lendzian, F |
Zeitschrift: | Biochimica et biophysica acta, Jg. 1774 (2007-10-01), Heft 10, S. 1254-63 |
Veröffentlichung: | Amsterdam : Elsevier Pub. Co., 2007 |
Medientyp: | academicJournal |
ISSN: | 0006-3002 (print) |
DOI: | 10.1016/j.bbapap.2007.07.001 |
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