Related Experiment Video
Updated: Aug 8, 2026
07:19
Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy
Published on: September 15, 2016
The elasticity of alpha-helices
1Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
The Journal of Chemical Physics
|July 23, 2005
Summary
Alpha-helices exhibit elasticity independent of amino acid sequence. Their persistence length, a measure of bending stiffness, is about 100 nm, similar in water and vacuum, and twice that of DNA.
Area of Science:
- Biophysics
- Computational Biology
- Materials Science
Background:
- Alpha-helices are fundamental protein structures.
- Understanding their mechanical properties is crucial for molecular biology and drug design.
Purpose of the Study:
- To investigate the elasticity of alpha-helices using computational simulations.
- To determine the bending modulus (persistence length) and compare it with theoretical models.
Main Methods:
- Equilibrium molecular-dynamics simulations were employed.
- Statistics of curvatures and twists were analyzed to compute elastic moduli.
- Simulations were performed in both aqueous solvent and vacuum.
Main Results:
- The bending modulus (persistence length) of alpha-helices is independent of the amino acid sequence.
- Helices in water are slightly softer than in vacuum.
- The persistence length of most alpha-helices is approximately 100 nm, twice that of DNA.
- Simulated helix properties align with elastic and isotropic rod models.
Conclusions:
- Alpha-helix elasticity is robust and sequence-independent.
- The persistence length is a key parameter characterizing helix mechanical behavior.
- Molecular dynamics simulations provide accurate predictions of helix mechanical properties.
Related Concept Videos
01:22Protein Folding
Overview
01:25Protein Folding
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
01:12Elasticity
Elasticity is the ability of an object to withstand the effects of distortion and to return to its original size and shape once the forces causing deformation are removed. When an elastic material deforms under the action of an external force, it experiences internal resistance to the deformation. However, if no external force is applied, it returns to its original state.
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
01:12Elastin is Responsible for Tissue Elasticity
Elastic fiber contains the protein elastin along with lesser amounts of other proteins and glycoproteins. The main property of elastin is that it will return to its original shape after being stretched or compressed. Elastic fibers are prominent in elastic tissues found in skin and the elastic ligaments of the vertebral column.
Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel. Dense regular elastic tissue contains elastin fibers and...
Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel. Dense regular elastic tissue contains elastin fibers and...
01:26Hooke's Law
Hooke's law, a pivotal principle in material science, establishes that the strain a material undergoes is directly proportional to the applied stress, defined by a factor called the modulus of elasticity or Young's modulus.
01:15Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.