| 245 GHz high-field EPR study of tyrosine-D zero and tyrosine-Z zero in mutants of photosystem II. | |
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MedLine Citation:
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PMID: 8547247 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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A 245 GHz 8.7 T high-field EPR study of tyrosine-D (TyrD zero) and tyrosine-Z (TyrZ zero) radicals of photosystem II (PSII) from Synechocystis PCC 6803 was carried out. Identical principal g values for the wild-type Synechocystis and spinach TyrD zero showed that the two radicals were in similar electrostatic environments. By contrast, the principal g values of the TyrD zero in the D2-His189Gln mutant of Synechocystis were different from those of the wild-type and spinach radicals and were similar to those of the tyrosyl radical in ribonucleotide reductase. These comparisons indicate that the D2-His189Gln mutant TyrD zero is not hydrogen-bonded or is only weakly so. The HF-EPR spectrum of TyrZ zero was obtained from the D2-Tyr160Phe mutant that lacks TyrD zero. The principal g values were nearly identical to those of the wild-type TyrD zero. The low-field edge of the TyrZ zero spectrum was much broader than at the other two principal g values and was also much broader than the TyrD zero spectrum. From the identical g values and previous work on tyrosyl radical g values [Un S., Atta M., Fontecave, M., & Rutherford, A. W. (1995) J. Am. Chem. Soc. 117, 10713-10719], it was concluded that TyrZ zero, like TyrD zero, is hydrogen-bonded The broadness of the gx component was interpreted as a distribution in strength of the hydrogen-bonding due to disorder in the protein environment about TyrZ zero. |
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Authors:
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S Un; X S Tang; B A Diner |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Biochemistry Volume: 35 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 1996 Jan |
Date Detail:
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Created Date: 1996-02-22 Completed Date: 1996-02-22 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 679-84 Citation Subset: IM |
Affiliation:
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URA1290 CNRS, Department Biologie Cellulaire et Moléculaire, CEA-Saclay, Gif-sur-Yvette, France. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Electron Spin Resonance Spectroscopy Free Radicals Hydrogen Bonding Mutation Photosynthetic Reaction Center Complex Proteins / chemistry* Photosystem II Protein Complex Spectroscopy, Fourier Transform Infrared Tyrosine / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Free Radicals; 0/Photosynthetic Reaction Center Complex Proteins; 0/Photosystem II Protein Complex; 55520-40-6/Tyrosine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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