Dimerization energetics of curli fiber subunits CsgA and CsgB

Curli fibers are functional amyloids that exhibit strong adhesion and robust self-assembly as biofilm structural components; however, the binding energetics and mechanical properties of wild-type curli are not well understood. To address this, we present dimer structures made up of the major and min...

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Bibliographic Details
Published in:npj computational materials 2019-02, Vol.5 (1), Article 27
Main Authors: Dunbar, Martha, DeBenedictis, Elizabeth, Keten, Sinan
Format: Article
Language:English
Subjects:
631/57
639/301/1034/1035
639/301/923/966
Adhesive strength
Binding energy
Biofilms
Characterization and Evaluation of Materials
Chemistry and Materials Science
Computational Intelligence
Dimerization
Dimers
Fibers
Free energy
Materials Science
Mathematical and Computational Engineering
Mathematical and Computational Physics
Mathematical Modeling and Industrial Mathematics
Mechanical properties
Modulus of elasticity
Molecular dynamics
Residues
Self-assembly
Theoretical
Thermodynamics
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Summary:Curli fibers are functional amyloids that exhibit strong adhesion and robust self-assembly as biofilm structural components; however, the binding energetics and mechanical properties of wild-type curli are not well understood. To address this, we present dimer structures made up of the major and minor curli subunits (CsgA and CsgB), perform free energy calculations to obtain absolute binding energies, and estimate the Young’s modulus and persistence length of curli fibers. Equilibrium molecular dynamics simulations are used to evaluate nonbonded interactions. Binding energies are most favorable for CsgB–CsgA, while CsgA–CsgA dimers have a higher binding energy than CsgB–CsgB despite possessing less favorable nonbonded interaction energies. Decomposing each potential of mean force of separation indicated that solvent effects positively impact CsgA–CsgA binding but not CsgB–CsgB and CsgB–CsgA. Charged residues and conserved polar residues were also notable contributors to attractive nonbonded interactions, underlining their importance in dimer assembly. Our findings elucidate sequence effects on binding energy contributions and establish theoretical limits for the elasticity, persistence length, and strength of curli fibers.
ISSN:2057-3960
2057-3960
DOI:10.1038/s41524-019-0164-5