title: Chalcogen bonding interactions between reducible sulfur and selenium compounds and models of zinc finger proteins.
abstract: Reducible sulfur and selenium (r-S/Se) compounds, defined as sulfur and selenium compounds not in the lowest -2 oxidation state (e.g., -1 to +6), release Zn(2+) from zinc-sulfur proteins such as zinc fingers (ZFs) and metallothionein. A series of density functional theory calculations was performed on donor-acceptor complexes between r-S/Se compounds and models of the Cys2His2, Cys3His and Cys4 ZF sites. These S⋯S/Se chalcogen bonding interactions consist of the donation of electron density from a S lone pair on the ZF model to a S/Se-X antibonding molecular orbital of the r-S/Se compound. The strength of the interaction was shown to be dependent upon the Lewis basicity of the ZF model (Cys4>Cys3His>Cys2His2) and the Lewis acidity of the r-S/Se compound as measured by the energy of the S/Se-X antibonding orbital. Interactions with the softer r-Se compounds were stronger than the r-S compounds, consistent with the greater reactivity of the former with ZF proteins.
authors.affiliation: Department of Science, Technology and Mathematics, Regent University, Virginia Beach, Virginia 23464, United States.
authors.forename: Patricia B
authors.initials: PB
authors.lastname: Lutz
authors.affiliation: Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Bayse
mesh_terms: D018011:Chalcogens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D012643:Selenium / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D016335:Zinc Fingers
chemical_list: D018011:Chalcogens; D013455:Sulfur; D012643:Selenium
keywords: Density functional theory; Organoselenium compounds; Organosulfur compounds; Zinc fingers