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Updated: Dec 28, 2025
X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
The structure of MP-4 from Mucuna pruriens at 2.22 Å resolution
Abha Jain1, Amit Kumar2, Meha Shikhi1
1Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India.
Abstract:
The structure of the MP-4 protein was previously determined at a resolution of 2.8 Å. Owing to the unavailability of gene-sequence information at the time, the side-chain assignment was carried out on the basis of a partial sequence available through Edman degradation, sequence homology to orthologs and electron density. The structure of MP-4 has now been determined at a higher resolution (2.22 Å) in another space group and all of the structural inferences that were presented in the previous report of the structure were validated. In addition, the present data allowed an improved assignment of side chains and enabled further analysis of the MP-4 structure, and the accuracy of the assignment was confirmed by the recently available gene sequence. The study reinforces the traditional concept that conservative interpretations of relatively low-resolution structures remain correct even with the availability of high-resolution data.
Insights
This study refined the MP-4 protein structure to 2.22 Å resolution, validating previous findings and improving side-chain assignments. It confirms that initial low-resolution interpretations of protein structures are reliable.
Area of Science:
- Structural Biology
- Protein Crystallography
Background:
- Previous MP-4 protein structure determined at 2.8 Å resolution.
- Initial side-chain assignment relied on partial sequencing and homology due to limited gene data.
Purpose of the Study:
- Determine the MP-4 protein structure at higher resolution.
- Validate previous structural inferences.
- Improve side-chain assignment accuracy.
Main Methods:
- X-ray crystallography to determine protein structure.
- Higher resolution data collection (2.22 Å) in a different space group.
- Utilized newly available gene sequence for validation.
Main Results:
- MP-4 protein structure solved at 2.22 Å resolution.
- All previous structural inferences were validated.
- Improved side-chain assignment confirmed by gene sequence data.
Conclusions:
- High-resolution data validated initial low-resolution structural interpretations.
- Accurate side-chain assignment is achievable with comprehensive data.
- Confirms the robustness of conservative structural analysis.
