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Updated: Jul 14, 2026
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Combining X-Ray Crystallography with Small Angle X-Ray Scattering to Model Unstructured Regions of Nsa1 from S. Cerevisiae
Published on: January 10, 2018
Conformational differences between Azotobacter vinelandii nitrogenase MoFe proteins as studied by small-angle X-ray
Mary C Corbett1, Yilin Hu, Aaron W Fay
1Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
Biochemistry
|June 15, 2007
Summary
The nitrogenase MoFe protein
Area of Science:
- Biochemistry
- Structural Biology
- Bioinorganic Chemistry
Background:
- The nitrogenase MoFe protein is crucial for nitrogen fixation, containing FeMoco and P-cluster metalloclusters.
- P-cluster biosynthesis occurs directly on the MoFe protein, unlike FeMoco assembly.
- Understanding P-cluster assembly is key to nitrogenase function.
Purpose of the Study:
- To investigate the relationship between P-cluster integrity and MoFe protein conformation.
- To characterize the structural changes in the DeltanifH MoFe protein variant.
- To elucidate early stages of P-cluster biosynthesis.
Main Methods:
- Small-angle X-ray scattering (SAXS) to determine protein size and shape.
- Iron (Fe) chelation studies to assess P-cluster accessibility.
- Biochemical and spectroscopic analysis of MoFe proteins from different genetic backgrounds.
Main Results:
- The DeltanifH MoFe protein exhibits a larger, more open conformation compared to wild-type.
- This opening correlates with P-cluster fragmentation into smaller [Fe4S4]-like units.
- The open structure suggests a potential intermediate state for P-cluster precursor insertion.
Conclusions:
- The DeltanifH MoFe protein represents an early biosynthetic intermediate.
- P-cluster fragmentation and protein opening facilitate precursor insertion.
- This conformational flexibility is vital for efficient P-cluster assembly.
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