Weak self-interactions of globular proteins studied by small-angle X-ray scattering and structure-based modeling
| Autor: | Tomás S. Plivelic, Shuji Kaieda, Mikael Lund, Bertil Halle |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Protein Conformation Globular protein Static Electricity FOS: Physical sciences Fatty Acid-Binding Proteins symbols.namesake Aprotinin X-Ray Diffraction Physics - Chemical Physics Protein Interaction Mapping Scattering Small Angle Materials Chemistry Animals Physics - Biological Physics Physical and Theoretical Chemistry Physics chemistry.chemical_classification Chemical Physics (physics.chem-ph) Quantitative Biology::Biomolecules Myoglobin Scattering Small-angle X-ray scattering Charge density Interaction model Biomolecules (q-bio.BM) Electrostatics Surfaces Coatings and Films Quantitative Biology - Biomolecules chemistry Chemical physics Biological Physics (physics.bio-ph) FOS: Biological sciences symbols Cattle van der Waals force Structure factor Monte Carlo Method |
| DOI: | 10.48550/arxiv.1408.6668 |
| Popis: | We investigate protein-protein interactions in solution by small-angle X-ray scattering (SAXS) and theoretical modeling. The structure factor for solutions of bovine pancreatic trypsin inhibitor (BPTI), myoglobin (Mb), and intestinal fatty acid-binding protein (IFABP) is determined from SAXS measurements at multiple concentrations, from Monte Carlo simulations with a coarse-grained structure-based interaction model, and from analytic approximate solutions of two idealized colloidal interaction models without adjustable parameters. By combining these approaches, we find that the structure factor is essentially determined by hard-core and screened electrostatic interactions. Other soft short-ranged interactions (van der Waals and solvation-related) are either individually insignificant or tend to cancel out. The structure factor is also not significantly affected by charge fluctuations. For Mb and IFABP, with small net charge and relatively symmetric charge distribution, the structure factor is well described by a hard-sphere model. For BPTI, with larger net charge, screened electrostatic repulsion is also important, but the asymmetry of the charge distribution reduces the repulsion from that predicted by a charged hard-sphere model with the same net charge. Such charge asymmetry may also amplify the effect of shape asymmetry on the protein-protein potential of mean force. Comment: 15 pages, 8 figures |
| Databáze: | OpenAIRE |
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