The Sulfur Shift: An Activation Mechanism for Periplasmic Nitrate Reductase and Formate Dehydrogenase

Nuno M. F. S. A. Cerqueira, Pedro Alexandrino Fernandes, Pablo Javier Gonzalez, José João Galhardas de Moura, Maria João Ramos

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

A structural rearrangement known as sulfur shift occurs in some Mo-containing enzymes of the DMSO reductase family. This mechanism is characterized by the displacement of a coordinating cysteine thiol (or SeCys in Fdh) from the first to the second shell of the Mo-coordination sphere metal. The hexa-coordinated Mo ion found in the as-isolated state cannot bind directly any exogenous ligand (substrate or inhibitors), while the penta-coordinated ion, attained upon sulfur shift, has a free binding site for direct coordination of the substrate. This rearrangement provides an efficient mechanism to keep a constant coordination number throughout an entire catalytic pathway. This mechanism is very similar to the carboxylate shift observed in Zn-dependent enzymes, and it has been recently detected by experimental means. In the present paper, we calculated the geometries and energies involved in the sulfur-shift mechanism using QM-methods (M06/(6-311++G(3df,2pd),SDD)//B3LYP/(6-31G(d),SDD)). The results indicated that the sulfur-shift mechanism provides an efficient way to enable the metal ion for substrate coordination.
Original languageEnglish
Pages (from-to)10766-10772
JournalInorganic Chemistry
Volume52
Issue number19
DOIs
Publication statusPublished - 2013

Keywords

  • MONONUCLEAR MOLYBDENUM ENZYMES
  • ESCHERICHIA-COLI
  • CRYSTAL-STRUCTURE
  • RIBONUCLEOTIDE REDUCTASE
  • CARBOXYLATE SHIFT
  • METHANE MONOOXYGENASE
  • DENSITY FUNCTIONALS
  • TRANSITION-ELEMENTS
  • RADICAL GENERATION
  • CATALYTIC CYCLE

Fingerprint Dive into the research topics of 'The Sulfur Shift: An Activation Mechanism for Periplasmic Nitrate Reductase and Formate Dehydrogenase'. Together they form a unique fingerprint.

Cite this