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Metallocenter Biosynthesis & Assembly

  1. Scott B. Mulrooney,
  2. Robert P. Hausinger

Published Online: 15 MAR 2006

DOI: 10.1002/0470862106.ia275

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Mulrooney, S. B. and Hausinger, R. P. 2006. Metallocenter Biosynthesis & Assembly. Encyclopedia of Inorganic Chemistry. .

Author Information

  1. Michigan State University, East Lansing, MI, USA

Publication History

  1. Published Online: 15 MAR 2006

Abstract

Metalloproteins have been characterized intensively for decades, yet only recently has progress been made in characterizing the mechanisms of biological metallocenter biosynthesis and assembly. Here, we describe how cellular synthesis of metal sites makes use of several recurring themes, often with multiple themes combined into a single pathway. In the simplest situation, binding of a metal ion to a biological ligand occurs by reversible thermodynamic control. However, the prevalence of metallocenters deeply buried within macromolecules, the exceedingly low concentrations of free metal ions within cells, and the sophisticated structures of many metal-containing active sites and cofactors provide evidence that alternative and more complex approaches also must exist. In some cases, metallochaperones are used to deliver the metal of interest to an apoprotein. In other cases the target protein undergoes posttranslational modification at the metal-binding site, either prior to or after the metal is bound. Many metallocenters contain additional components that are added along with the metal ion or used to form a preassembled metal-containing cofactor. Scaffolding proteins may be used to provide a framework for construction of the cofactor. Electron transfer reactions involving the metal, an added compound, or the protein ligand can participate in activation. Finally, molecular chaperones that bind to and alter the conformation of the target apoprotein may be utilized. In many cases, the function of the molecular chaperone is coupled to nucleotide triphosphate hydrolysis.

Keywords:

  • apoprotein;
  • cofactor;
  • heme;
  • iron–sulfur clusters;
  • metallochaperone;
  • metallocenter;
  • molybdopterin;
  • scaffold proteins