Rapid X-ray photoreduction of dimetal-oxygen cofactors in ribonucleotide reductase.
(2013) In Journal of Biological Chemistry- Abstract
- Prototypic dinuclear metal cofactors with varying metallation constitute a class of O2-activating catalysts in numerous enzymes such as ribonucleotide reductase (RNR1). Reliable structures are required to unravel the reaction mechanisms. However, protein crystallography data may be compromised by X-ray photoreduction (XPR). We studied XPR of Fe(III)Fe(III) and Mn(III)Fe(III) sites in the R2 subunit of Chlamydia trachomatis RNR using X-ray absorption spectroscopy. Rapid and biphasic XPR kinetics at 20 K and 80 K for both cofactor types suggested sequential formation of (III,II) and (II,II) species and similar redox potentials of Fe and Mn sites. Comparing with typical X-ray doses in crystallography implies that (II,II) states are reached in... (More)
- Prototypic dinuclear metal cofactors with varying metallation constitute a class of O2-activating catalysts in numerous enzymes such as ribonucleotide reductase (RNR1). Reliable structures are required to unravel the reaction mechanisms. However, protein crystallography data may be compromised by X-ray photoreduction (XPR). We studied XPR of Fe(III)Fe(III) and Mn(III)Fe(III) sites in the R2 subunit of Chlamydia trachomatis RNR using X-ray absorption spectroscopy. Rapid and biphasic XPR kinetics at 20 K and 80 K for both cofactor types suggested sequential formation of (III,II) and (II,II) species and similar redox potentials of Fe and Mn sites. Comparing with typical X-ray doses in crystallography implies that (II,II) states are reached in <1 s in such studies. First-sphere metal coordinations and metal-metal distances differed after chemical reduction at room temperature and after XPR at cryogenic temperatures, as corroborated by model structures from density functional theory calculations. The inter-metal distances in the (II,II) states, however, are similar to R2 crystal structures. Therefore, crystal data of initially oxidized R2-type proteins mostly contain photoreduced (II,II) cofactors, which deviate from the native structures functional in O2-activation, explaining observed variable metal ligation motifs. This situation may be remedied by novel femtosecond free-electron-laser protein crystallography techniques. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3559900
- author
- Sigfridsson Clauss, Kajsa LU ; Chernev, Petko ; Leidel, Nils ; Popovic-Bijelic, Ana ; Graslund, Astrid and Haumann, Michael
- organization
- publishing date
- 2013-02-11
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Biological Chemistry
- publisher
- American Society for Biochemistry and Molecular Biology
- external identifiers
-
- pmid:23400774
- wos:000317114000008
- scopus:84875993794
- pmid:23400774
- ISSN
- 1083-351X
- DOI
- 10.1074/jbc.M112.438796
- language
- English
- LU publication?
- yes
- id
- 6319b8b2-a53d-40f3-bced-69e0b06607a9 (old id 3559900)
- date added to LUP
- 2016-04-01 09:58:28
- date last changed
- 2022-01-25 18:37:55
@article{6319b8b2-a53d-40f3-bced-69e0b06607a9,
abstract = {{Prototypic dinuclear metal cofactors with varying metallation constitute a class of O2-activating catalysts in numerous enzymes such as ribonucleotide reductase (RNR1). Reliable structures are required to unravel the reaction mechanisms. However, protein crystallography data may be compromised by X-ray photoreduction (XPR). We studied XPR of Fe(III)Fe(III) and Mn(III)Fe(III) sites in the R2 subunit of Chlamydia trachomatis RNR using X-ray absorption spectroscopy. Rapid and biphasic XPR kinetics at 20 K and 80 K for both cofactor types suggested sequential formation of (III,II) and (II,II) species and similar redox potentials of Fe and Mn sites. Comparing with typical X-ray doses in crystallography implies that (II,II) states are reached in <1 s in such studies. First-sphere metal coordinations and metal-metal distances differed after chemical reduction at room temperature and after XPR at cryogenic temperatures, as corroborated by model structures from density functional theory calculations. The inter-metal distances in the (II,II) states, however, are similar to R2 crystal structures. Therefore, crystal data of initially oxidized R2-type proteins mostly contain photoreduced (II,II) cofactors, which deviate from the native structures functional in O2-activation, explaining observed variable metal ligation motifs. This situation may be remedied by novel femtosecond free-electron-laser protein crystallography techniques.}},
author = {{Sigfridsson Clauss, Kajsa and Chernev, Petko and Leidel, Nils and Popovic-Bijelic, Ana and Graslund, Astrid and Haumann, Michael}},
issn = {{1083-351X}},
language = {{eng}},
month = {{02}},
publisher = {{American Society for Biochemistry and Molecular Biology}},
series = {{Journal of Biological Chemistry}},
title = {{Rapid X-ray photoreduction of dimetal-oxygen cofactors in ribonucleotide reductase.}},
url = {{http://dx.doi.org/10.1074/jbc.M112.438796}},
doi = {{10.1074/jbc.M112.438796}},
year = {{2013}},
}