Proline scanning mutagenesis reveals non-native fold in the molten globule state of equine beta-lactoglobulin.
Abstract: The secondary structure in the molten globule state (an equilibrium analogue of a burst-phase folding intermediate) of equine beta-lactoglobulin was investigated by changes in the circular dichroic spectrum induced by a series of site-directed proline substitutions. The results challenge the structural picture obtained from previous hydrogen/deuterium exchange experiments. A stable non-native alpha-helix was found to exist in the region corresponding to the eighth strand (H strand) in the native structure, where the backbone amide protons are the most strongly protected from exchange. Therefore, the backbone topology in the folding core is significantly different from that in the native structure. This indicates that the burst-phase folding intermediate of beta-lactoglobulin is a trapped species because of misfolded backbone topology.
Publication Date: 2006-12-01 PubMed ID: 17176068DOI: 10.1021/bi061420pGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research investigates the molten globule state of equine beta-lactoglobulin, and suggests that its backbone topology is significantly different from its native structure due to a stable non-native alpha-helix strand.
Objective of the Study
- This research seeks to critically examine the secondary structure of the molten globule state of equine beta-lactoglobulin, using changes in the circular dichroic spectrum that are induced by proline substitutions at specific sites.
Methodology of the Study
- The researchers utilized site-directed proline substitutions to induce changes in the circular dichroic spectrum. This was done to explore the secondary structure in the molten globule state, an equilibrium analogue of a burst-phase folding intermediate, of equine beta-lactoglobulin.
Findings of the Study
- The results from this study dispute the structural understanding drawn from previous hydrogen/deuterium exchange experiments.
- A stable non-native alpha-helix was found in the region corresponding to the eighth strand (H strand) in the native structure. In this region, the backbone amide protons are most strongly shielded from exchange.
- These findings suggest that the backbone topology in the folding core of the molten globule state is significantly different from that in the native structure.
- The results lead the researchers to believe that the burst-phase folding intermediate of beta-lactoglobulin manifests as a trapped species due to misfolded backbone topology.
Implication of the Research
- The research provides potentially significant insights into the structural changes experienced by equine beta-lactoglobulin in its molten globule state.
- By highlighting that the folding intermediate of beta-lactoglobulin is a trapped species, these findings could contribute to broader understanding of protein folding and misfolding mechanisms, with potential benefits to fields such as structural biology, biotechnology and biochemistry.
Cite This Article
APA
Nakagawa K, Tokushima A, Fujiwara K, Ikeguchi M.
(2006).
Proline scanning mutagenesis reveals non-native fold in the molten globule state of equine beta-lactoglobulin.
Biochemistry, 45(51), 15468-15473.
https://doi.org/10.1021/bi061420p Publication
Researcher Affiliations
- Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan.
MeSH Terms
- Amino Acid Sequence
- Amino Acid Substitution / genetics
- Animals
- Circular Dichroism
- Horses
- Lactoglobulins / chemistry
- Lactoglobulins / genetics
- Molecular Sequence Data
- Mutagenesis, Insertional
- Proline / genetics
- Protein Conformation
- Protein Folding
- Protein Structure, Secondary / genetics
- Thermodynamics
Citations
This article has been cited 5 times.- Raskatov JA, Teplow DB. Using chirality to probe the conformational dynamics and assembly of intrinsically disordered amyloid proteins. Sci Rep 2017 Oct 2;7(1):12433.
- Sun L, Nakamae N, Ichikawa N. The region from phenylalanine-28 to lysine-50 of a yeast mitochondrial ATPase inhibitor (IF1) forms an α-helix in solution. J Bioenerg Biomembr 2015 Dec;47(6):457-65.
- Ikeguchi M. Transient non-native helix formation during the folding of β-lactoglobulin. Biomolecules 2014 Feb 13;4(1):202-16.
- Romero A, Cakir I, Vaslet CA, Stuart RC, Lansari O, Lucero HA, Nillni EA. Role of a pro-sequence in the secretory pathway of prothyrotropin-releasing hormone. J Biol Chem 2008 Nov 14;283(46):31438-48.
- Yanagida Y, Yoshida K, Ohtomo M, Fujiwara K, Ikeguchi M. Mechanisms of helix induction by the closed loop. Protein Sci 2025 Jun;34(6):e70171.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists