NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Exploration of the Structural Environment of the Iron-Sulfur Cluster in Putidaredoxin by Nitrogen-15 NMR Spectroscopy of Selectively Labeled Cysteine Residues
Published
Author(s)
Fahriye N. Sari, Marcia J. Holden, M P. Mayhew, V L. Vilker, B Coxon
Abstract
Putidaredoxin is a di-iron protein whose paramagnetic region is not well characterized by 1H detected NMR. We have studied the structure of this region in greater detail by directly observed 15N NMR of oxidized and reduced putidaredoxin preparations in which the six cysteine residues are selectively labeled with 15N. A new method for preparation of a stable form of reduced putidaredoxin has been developed. The 15N NMR spectra of the oxidized and reduced forms are characteristically different, and we have measured and compared 15N chemical shifts, spin-lattice relaxation times (T1) and chemical shift/temperature dependences for both forms. Evidence for localized valencies of the iron atoms in the reduced form is presented. From the 15N T1 values of the oxidized form, reduced distances of the cysteine backbone 15N nuclei from the center of the Fe2S2 cluster have been calculated. These distances are consistent with those calculated from X-ray crystal structure data for five ferredoxins, and confirm the structural similarity of the Fe2S2 clusters in putidaredoxin and in these ferredoxins in the oxidized state.
Citation
Biochemical and Biophysical Research Communications
Sari, F.
, Holden, M.
, Mayhew, M.
, Vilker, V.
and Coxon, B.
(1998),
Exploration of the Structural Environment of the Iron-Sulfur Cluster in Putidaredoxin by Nitrogen-15 NMR Spectroscopy of Selectively Labeled Cysteine Residues, Biochemical and Biophysical Research Communications
(Accessed October 10, 2025)