A Delicate Interplay of Structure, Dynamics, and Thermodynamics for Function: A High Pressure NMR Study of Outer Surface Protein A
| Autor: | Alana K. Simorellis, Shohei Koide, Akihiro Maeno, Kazuyuki Akasaka, Kazumi Hata, Ryo Kitahara, Shigeyuki Yokoyama |
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| Jazyk: | angličtina |
| Předmět: |
Models
Molecular Protein Folding Lipoproteins Biophysics Epitope Fluorescence spectroscopy Protein Structure Secondary Mole Pressure Borrelia burgdorferi Conformational isomerism Nuclear Magnetic Resonance Biomolecular biology Chemistry Protein biology.organism_classification bacterial infections and mycoses Bacterial vaccine Crystallography Spectrometry Fluorescence Antigens Surface Bacterial Vaccines Thermodynamics Protein folding Function (biology) Bacterial Outer Membrane Proteins |
| Zdroj: | Biophysical Journal. (4):916-926 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/j.bpj.2011.12.010 |
| Popis: | Outer surface protein A (OspA) is a crucial protein in the infection of Borrelia burgdorferi causing Lyme disease. We studied conformational fluctuations of OspA with high-pressure 15N/1H two-dimensional NMR along with high-pressure fluorescence spectroscopy. We found evidence within folded, native OspA for rapid local fluctuations of the polypeptide backbone in the nonglobular single layer β-sheet connecting the N- and C-terminal domains with τ << ms, which may give the two domains certain independence in mobility and thermodynamic stability. Furthermore, we found that folded, native OspA is in equilibrium (τ >> ms) with a minor conformer I, which is almost fully disordered and hydrated for the entire C-terminal part of the polypeptide chain from β8 to the C-terminus. Conformer I is characterized with ΔG0 = 32 ± 9 kJ/mol and ΔV0 = −140 ± 40 mL/mol, populating only ∼0.001% at 40°C at 0.1 MPa, pH 5.9. Because in the folded conformer the receptor binding epitope of OspA is buried in the C-terminal domain, its transition into conformer I under in vivo conditions may be critical for the infection of B. burgdorferi. The formation and stability of the peculiar conformer I are apparently supported by a large packing defect or cavity located in the C-terminal domain. |
| Databáze: | OpenAIRE |
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