Reversible Conversion of Disulfide/Dithiolate Occurring at a Vanadium(IV) Center: A Biomimetic System for Redox Exchange in Vanabin

Cheng Hsun Lee, Ding Jyun Lin, Hung Ruei Pan, John Wu, Hsin Kuan Liu, Hua Fen Hsu

Research output: Contribution to journalArticlepeer-review

Abstract

Ascidians use a class of cysteine-rich proteins generally referred to as vanabins to reduce vanadium ions, one of the many biological processes that involve the redox conversion between disulfide and dithiolate mediated by transition-metal ions. To further understand the nature of disulfide/dithiolate exchange facilitated by a vanadium center, we report herein a six-coordinate non-oxido VIVcomplex containing an unbound disulfide moiety, [VIV(PS3″)(PS1″S-S)] (1) (PS3″ = [P(C6H3-3-Me3Si-2-S)3]3-, where PS1″S-Sis a disulfide form of PS3″). Complex 1 is obtained from a reaction of previously reported [VV(PS3″)(PS2″SH)] (2) (PS2″SH= [P(C6H3-3-Me3Si-2-SH)(C6H3-3-Me3Si-2-S)2] with TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidin-1-yl)oxyl) via hydrogen atom transfer. Importantly, complex 1 can be reduced by two electrons to form an eight-coordinate VIVcomplex, [VIV(PS3″)2]2-(4). The reaction can be reversed through a two-electron oxidation process to regenerate complex 1. The redox pathways both proceed through a common intermediate, [V(PS3″)2]-(3), that has been previously reported as a resonance form of VV-dithiolate and a VIV-(thiolate)(thiyl-radical) species. This work demonstrates an unprecedented example of reversible disulfide/dithiolate interconversion mediated by a VIVcenter, as well as provides insights into understanding the function of VVreductases in vanabins.

Original languageEnglish
Pages (from-to)19882-19889
Number of pages8
JournalInorganic Chemistry
Volume61
Issue number49
DOIs
Publication statusPublished - 2022 Dec 12

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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