Topological Switching between an α−β Parallel Protein and a Remarkably Helical Molten Globule
| Autor: | Adrie H. Westphal, Carlo P. M. van Mierlo, Simon Lindhoud, Marije aan den Toorn, Sanne M. Nabuurs |
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| Rok vydání: | 2009 |
| Předmět: |
Protein Folding
Phenylalanine Flavodoxin Membrane transport and intracellular motility [NCMLS 5] Biochemie Topology Biochemistry Protein Structure Secondary Catalysis state Colloid and Surface Chemistry Protein structure hydrogen-exchange Protein Structure Quaternary flavodoxin-ii Conformational isomerism Protein secondary structure Conserved Sequence Topology (chemistry) Renal disorder [IGMD 9] VLAG apomyoglobin biology Chemistry energy landscape on-pathway unfolded molecules Energy landscape General Chemistry biology.organism_classification Molten globule Folding (chemistry) pathway folding intermediate Crystallography Models Chemical Azotobacter vinelandii Thermodynamics Tyrosine structural-characterization Apoproteins azotobacter-vinelandii apoflavodoxin |
| Zdroj: | Journal of the American Chemical Society, 131, 8290-5 Journal of the American Chemical Society, 131, 23, pp. 8290-5 Journal of the American Chemical Society, 131(23), 8290-8295 Journal of the American Chemical Society 131 (2009) 23 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja9014309 |
| Popis: | Item does not contain fulltext Partially folded protein species transiently exist during folding of most proteins. Often these species are molten globules, which may be on- or off-pathway to native protein. Molten globules have a substantial amount of secondary structure but lack virtually all the tertiary side-chain packing characteristic of natively folded proteins. These ensembles of interconverting conformers are prone to aggregation and potentially play a role in numerous devastating pathologies, and thus attract considerable attention. The molten globule that is observed during folding of apoflavodoxin from Azotobacter vinelandii is off-pathway, as it has to unfold before native protein can be formed. Here we report that this species can be trapped under nativelike conditions by substituting amino acid residue F44 by Y44, allowing spectroscopic characterization of its conformation. Whereas native apoflavodoxin contains a parallel beta-sheet surrounded by alpha-helices (i.e., the flavodoxin-like or alpha-beta parallel topology), it is shown that the molten globule has a totally different topology: it is helical and contains no beta-sheet. The presence of this remarkably nonnative species shows that single polypeptide sequences can code for distinct folds that swap upon changing conditions. Topological switching between unrelated protein structures is likely a general phenomenon in the protein structure universe. |
| Databáze: | OpenAIRE |
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