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A Refined Model for [Fe 3 S 4 ] 0 Clusters in Proteins
Author(s) -
Bentrop Detlef,
Bertini Ivano,
Borsari Marco,
Cosenza Grazia,
Luchinat Claudio,
Niikura Yohei
Publication year - 2000
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20001016)39:20<3620::aid-anie3620>3.0.co;2-t
Subject(s) - protonation , chemistry , cluster (spacecraft) , valence (chemistry) , iron–sulfur cluster , crystallography , proton , hyperfine structure , cysteine , proton nmr , chemical physics , inorganic chemistry , computational chemistry , stereochemistry , ion , atomic physics , organic chemistry , physics , enzyme , quantum mechanics , computer science , programming language
A “merry‐go‐round” of iron valences is seen in an [Fe 3 S 4 ] 0 cluster with cysteine ligands. This phenomena is revealed by the observation of hyperfine‐shifted 1 H NMR signals from the coordinated cysteine units, and the disappearance of these signals upon protonation of the cluster at low pH values. The proton binds to each of the three μ ‐bridging sulfides for a fraction of time (see scheme). The protonation of one μ ‐S causes the two iron atoms bridged by that μ ‐S to form a mixed‐valence pair and the exchange of the proton from one μ ‐S to another causes a change in the iron valences in the cluster.