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14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Modeling side-on NO coordination to type 2 copper in nitrite reductase: structures, energetics, and bonding
Ingar H Wasbotten1, Abhik Ghosh
1Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
Journal of the American Chemical Society
|November 3, 2005
Summary
Density Functional Theory (DFT) calculations identified novel copper-nitrosyl species ({CuNO}10 and {CuNO}11) in nitrite reductase (CuNIR). The {CuNO}11 species shows favorable energetics and geometry for CuNIR active sites.
Area of Science:
- Biochemistry
- Computational Chemistry
- Enzyme Mechanisms
Background:
- Nitrite reductase (NiR) enzymes are crucial in nitrogen cycling.
- Type 2 copper sites are implicated in NiR enzymatic activity.
- Understanding the coordination chemistry of copper-nitrosyl species is vital for NiR mechanism elucidation.
Purpose of the Study:
- To investigate the existence and properties of metastable copper-nitrosyl species.
- To determine the preferred coordination mode of nitrosyl (NO) to copper in NiR.
- To compare computational models with experimental crystallographic data for CuNIR intermediates.
Main Methods:
- Density Functional Theory (DFT) calculations were employed.
- Metastable {CuNO}10 and {CuNO}11 species were modeled.
- Energetic favorability and geometric parameters were analyzed.
Main Results:
- DFT calculations confirm the existence of side-on {CuNO}10 and {CuNO}11 species.
- The {CuNO}11 species exhibits more favorable energetics for NO coordination.
- Geometric parameters of {CuNO}11 align better with crystallographic data of a CuNIR intermediate.
Conclusions:
- Metastable {CuNO}10 and {CuNO}11 species are relevant to the type 2 copper site in CuNIR.
- Side-on NO coordination is energetically favored for the {CuNO}11 species.
- {CuNO}11 provides a better structural model for CuNIR intermediates compared to {CuNO}10.
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