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Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy
Published on: August 15, 2014
Structure of cytochrome c nitrite reductase
O Einsle1, A Messerschmidt, P Stach
1Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Martinsried, Germany. einsle@biochem.mpg.de
Nature
|August 10, 1999
Summary
The crystal structure of cytochrome c nitrite reductase was determined, revealing its role in the biological nitrogen cycle. This enzyme facilitates the reduction of nitrite to ammonia, crucial for anaerobic energy metabolism.
Area of Science:
- Biochemistry
- Microbiology
- Structural Biology
Background:
- Cytochrome c nitrite reductase is vital for the biological nitrogen cycle, catalyzing nitrite to ammonia conversion.
- It plays a key role in the anaerobic energy metabolism of dissimilatory nitrate ammonification.
Purpose of the Study:
- To determine the crystal structure of cytochrome c nitrite reductase from Sulfurospirillum deleyianum.
- To elucidate the enzyme's reaction mechanism and active site.
- To identify conserved protein families with similar heme arrangements.
Main Methods:
- X-ray crystallography
- Multi-wavelength anomalous dispersion (MAD) methods
- Spectroscopic analysis
Main Results:
- The crystal structure of cytochrome c nitrite reductase was solved, revealing a functional dimer.
- The enzyme contains 10 c-type heme groups and an unusual lysine-coordinated high-spin heme at the active site.
- A reaction scheme for nitrite transformation was proposed based on structural and spectroscopic data.
Conclusions:
- The determined structure provides insights into the catalytic mechanism of nitrite reduction.
- A conserved family of multiheme cytochromes with conserved heme orientation but variable structure and function was identified.
