Sulfur K-Edge XAS Studies of the Effect of DNA Binding on the [Fe₄S₄] Site in EndoIII and MutY.

ABSTRACT: S K-edge X-ray absorption spectroscopy (XAS) was used to study the [Fe₄S₄] clusters in the DNA repair glycosylases EndoIII and MutY to evaluate the effects of DNA binding and solvation on Fe-S bond covalencies (i.e., the amount of S 3p character mixed into the Fe 3d valence orbitals). Increased covalencies in both iron-thiolate and iron-sulfide bonds would stabilize the oxidized state of the [Fe₄S₄] clusters. The results are compared to those on previously studied [Fe₄S₄] model complexes, ferredoxin (Fd), and to new data on high-potential iron-sulfur protein (HiPIP). A limited decrease in covalency is observed upon removal of solvent water from EndoIII and MutY, opposite to the significant increase observed for Fd, where the

SUBMITTER: Ha Y 

PROVIDER: S-EPMC5568943 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature