CuA centers and their biosynthetic models in azurin

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DOI: 10.1007/s00775-010-0625-2

Cite this article as:
Savelieff, M.G. & Lu, Y. J Biol Inorg Chem (2010) 15: 461. doi:10.1007/s00775-010-0625-2

Abstract

CuA is a binuclear copper center that functions as an electron transfer agent, cycling between a reduced Cu(I)Cu(I) state and an oxidized mixed-valence Cu(+1.5)···Cu(+1.5) state. The copper ions are bridged by two cysteine thiolate ligands and form a copper–copper bond, the first reported of its kind in Nature. Such a “diamond-core” Cu2S(Cys)2 structure allows an unpaired electron to be completely delocalized over the two copper ions and contributes to its highly efficient electron transfer properties. This review provides accounts of how the CuA center was structurally characterized and highlights its salient spectroscopic properties. In the process, it introduces the CuA center in four different systems—native protein systems, soluble protein truncates of native proteins, synthetic models using organic molecules, and biosynthetic models using proteins as ligands—with a greater emphasis on biosynthetic models of CuA, especially on new, deeper insights gained from their studies.

Keywords

Biosynthesis Electron transfer Protein engineering Cytochrome c oxidase 

Abbreviations

CcO

Cytochrome c oxidase

CD

Circular dichroism

CT

Charge transfer

CuA-Ami

CuA in amicyanin

CuA-Az

CuA in azurin

ENDOR

Electron–nuclear double resonance

EPR

Electron paramagnetic resonance

ET

Electron transfer

EXAFS

Extended X-ray absorption fine structure

HOMO

Highest occupied molecular orbital

MCD

Magnetic circular dichroism

MO

Molecular orbital

N2OR

Nitrous oxide reductase

RR

Resonance Raman

T1

Type 1

T2

Type 2

XAS

X-ray absorption spectroscopy

Copyright information

© SBIC 2010

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of Illinois at Urbana-ChampaignUrbanaUSA
  2. 2.Department of ChemistryMichigan State University DubaiDubaiUnited Arab Emirates

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