@article{33c1dc63e4cc4d0cb5169a58e4eae9dd,
title = "Unpaired Electron Spin Density Distribution across Reduced [2Fe-2S] Cluster Ligands by 13Cβ-Cysteine Labeling",
abstract = "Iron-sulfur clusters are one of the most versatile and ancient classes of redox mediators in biology. The roles that these metal centers take on are predominantly determined by the number and types of coordinating ligands (typically cysteine and histidine) that modify the electronic structure of the cluster. Here we map the spin density distribution onto the cysteine ligands for the three major classes of the protein-bound, reduced [2Fe-2S](His)n(Cys)4-n (n = 0, 1, 2) cluster by selective cysteine-13Cβ isotope labeling. The spin distribution is highly asymmetric in all three systems and delocalizes further along the reduced Fe2+ ligands than the nonreducible Fe3+ ligands for all clusters studied. The preferential spin transfer onto the chemically reactive Fe2+ ligands is consistent with the structural concept that the orientation of the cluster in proteins is not arbitrarily decided, but rather is optimized such that it is likely to facilitate better electronic coupling with redox partners. The resolution of all cysteine-13Cβ hyperfine couplings and their assignments provides a measure of the relative covalencies of the metal-thiolate bonds not readily available to other techniques.",
author = "Taguchi, {Alexander T.} and Yoshiharu Miyajima-Nakano and Risako Fukazawa and Lin, {Myat T.} and Amgalanbaatar Baldansuren and Gennis, {Robert B.} and Kazuya Hasegawa and Takashi Kumasaka and Dikanov, {Sergei A.} and Toshio Iwasaki",
note = "Funding Information: This investigation was supported in part by the International Collaborations in Chemistry Grant from JSPS (T.I.) and NSF (CHE-1026541 to S.A.D.), the JSPS Grant-in-Aid 24659202 (T.I.), the DE-FG02-87ER13716 (R.B.G.) and DE-FG02-08ER15960 (S.A.D., pulsed EPR work) Grants from the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Sciences, U.S. DOE, and NIGMS Roadmap Initiative (R01GM075937). A.T.T. gratefully acknowledges support as a JSPS Postdoctoral Fellow (P14415). Funding Information: This investigation was supported in part by the International Collaborations in Chemistry Grant from JSPS (T.I.) and NSF (CHE-1026541 to S.A.D.), the JSPS Grant-in-Aid 24659202 (T.I.), the DE-FG02-87ER13716 (R.B.G.) and DE-FG02-08ER15960 (S.A.D., pulsed EPR work) Grants from the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Sciences, U.S. DOE, and NIGMS Roadmap Initiative (R01GM075937). Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",
year = "2018",
month = jan,
day = "16",
doi = "10.1021/acs.inorgchem.7b02676",
language = "English (US)",
volume = "57",
pages = "741--746",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "2",
}