Elasticity, strength and resilience: A comparative study on mechanical signatures of α-Helix, β-sheet and tropocollagen domains

Abstract

In biology, structural design and materials engineering is unified through formation of hierarchical features with atomic resolution, from nano to macro. Three molecular building blocks are particularly prevalent in all structural protein materials: alpha helices (AHs), beta-sheets (BSs) and tropocollagen (TC). In this article we present a comparative study of these three key building blocks by focusing on their mechanical signatures, based on results from full-atomistic simulation studies. We fi nd that each of the basic structures is associated with a characteristic material behavior: AH protein domains provide resilience at large deformation through energy dissipation at low force levels, BS protein domains provide great strength under shear loading, and tropocollagen molecules provide large elasticity for deformation recovery. This suggests that AHs, BSs, and TC molecules have mutually exclusive mechanical signatures. We correlate each of these basic properties with the molecule's structure and the associated fundamental rupture mechanisms. Our study may enable the use of abundant protein building blocks in nanoengineered materials, and may provide critical insight into basic biological mechanisms for bio-inspired nanotechnologies. The transfer towards the design of novel nanostructures could lead to new multifunctional and mechanically active, tunable, and changeable materials.

New three-dimensional model based on finite element method of bone nanostructure: single TC molecule scale level

“…The characteristic triple helical structure provides the structural basis for this continuous stiffening behavior. The obtained TC force-reduced extension curve (in orange in Figure 4) has the same shape of that found by Buehler and Keten (Buehler & Keten 2008), Sun and co-authors (Sun et al 2002) and Bozec and Horton (Bozec & Horton 2005). The TC molecule geometric parameters are similar to those tested in the current work.…”

Mechanical Model of Hydrogen Bonds in Protein Molecules

“…This results are in good agreement with the stiffness predicted by [9] for this protein molecule (0.06-0.08N/m). To study elasticity and strength of secondary structures of protein molecules [1] compared the force-extension behavior of α-helices, β-sheets and tropocollagen domains in protein molecules. Their results are provided by using atomistic modeling of nano-mechanical response of the protein molecules at ultra-slow deformation rates.…”

“…Unique physical properties of biomaterials such as selfassembly, self-healing, adaptability and changeability have encouraged researchers to devote special attention to designing and fabricating synthetic materials that have similar properties [1,2,3]. These unique properties are facilitated by building blocks of biomaterials, proteins.…”

“…Laser tweezer is another experimental technique used to analyze material properties in molecular level [8]. Researchers also conducted computational simulations to predict mechanical properties of protein molecules [9,10,11].…”

Physical properties of honeybee silk: a review

“…Elucidating the relation between structure and material properties and multi-scale behaviour of protein assemblies such as the honeybee ά-helical silk represents a grand challenge at the interface of materials science and biology (Ackbarow et al 2009). This gap in understanding can be closed by systematically studying the material properties of hierarchical protein struc-tures and their effect on the macroscopic proper-ties, an approach part of a larger effort to study the role of materials in biology, referred to by Buehler and Keten (2008) as materiomics.…”