Related Experiment Video
Updated: Jun 23, 2026

09:51
Investigating Protein Sequence-structure-dynamics Relationships with Bio3D-web
Published on: July 16, 2017
Inter-helical interactions in membrane proteins: analysis based on the local backbone geometry and the side chain
Anupam Nath Jha1, Saraswathi Vishveshwara
1Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
Journal of Biomolecular Structure & Dynamics
|April 24, 2009
Summary
This study quantitatively analyzes helix-helix packing in alpha-helical membrane proteins. A single parameter, alpha, accurately describes interactions, revealing preferences in anti-parallel and parallel helix arrangements.
Area of Science:
- Structural Biology
- Biophysics
- Computational Biology
Background:
- Numerous helical membrane protein structures are available.
- Understanding helix-helix packing is crucial for protein function and modeling.
Purpose of the Study:
- To systematically investigate the mode of helix-helix packing in alpha-helical membrane proteins.
- To develop a quantitative method for describing inter-helical interactions.
Main Methods:
- Analyzed a dataset of alpha-helical membrane protein structures.
- Defined local coordinate axes for helical residues and contact criteria based on atom-atom contacts.
- Derived a single parameter (alpha) to characterize helix-helix orientation and interaction.
Main Results:
- The parameter alpha accurately captures helix-helix interaction details.
- A specific range of alpha values is preferred for anti-parallel helix interactions.
- Parallel helix interactions show a lesser preference, while perpendicular helices exhibit no preference.
Conclusions:
- Anti-parallel helices are well-packed, supporting existing views.
- Interactions between parallel helices are complex and non-trivial.
- The quantitative analysis of packing may aid in modeling helical membrane proteins.
Related Concept Videos
Protein Folding
Overview
Protein 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...
Protein Organization
Overview
Protein Organization
Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
The primary structure of a protein is its amino acid sequence.
Protein and Protein Structure
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...
A protein's shape is critical to its function. For example, an enzyme can...
Noncovalent Attractions in Biomolecules
Noncovalent attractions are associations within and between molecules that influence the shape and structural stability of complexes. These interactions differ from covalent bonding in that they do not involve sharing of electrons.
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...

