التفاصيل البيبلوغرافية
| العنوان: |
Changes in hydrogen-bond strengths explain reduction potentials in 10 rubredoxin variants. |
| المؤلفون: |
I.-Jin Lin, Gebel, Erika B., Machonkin, Timothy E., Westler, William M., Markley, John L. |
| المصدر: |
Proceedings of the National Academy of Sciences of the United States of America; 10/11/2005, Vol. 102 Issue 41, p14581-14586, 6p |
| مصطلحات موضوعية: |
HYDROGEN bonding, AMINO acid sequence, SULFUR, NUCLEAR magnetic resonance spectroscopy, PROTEIN research, METALLOPROTEINS |
| مستخلص: |
The rubredoxin from Ciostridium pasteurianum (CpRd) provides an excellent system for investigating how the protein sequence modulates the reduction potential of the active site in an iron-sulfur protein. 15N NMR spectroscopy has allowed us to determine with unprecedented accuracy the strengths of all six key hydrogen bonds between protein backbone amides and the sulfur atoms of the four cysteine residues that ligate the iron in the oxidized (FeII) and reduced (FeIII) forms of wild-type CpRd and nine mutants (V44G, V44A, V441, V441, V86, V8A, V81, V8L and V8G/V44G). The length (or strength) of each hydrogen bond was inferred from the magnitude of electron spin delocalized across the hydrogen bond from the iron atom onto the nitrogen. The aggregate lengths of these six hydrogen bonds are shorter in both oxidation states in variants with higher reduction potential than in those with lower reduction potential. Differences in aggregate hydrogen bonding upon reduction correlate linearly with the published reduction potentials for the 10 CpRd variants, which span 126 mV. Sequence effects on the reduction potential can be explained fully by their influence on hydrogen-bond strengths. [ABSTRACT FROM AUTHOR] |
|
Copyright of Proceedings of the National Academy of Sciences of the United States of America is the property of National Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| قاعدة البيانات: |
Complementary Index |
