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Protein and Protein Structure

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...

Protein Organization

Protein Organization

Protein Organization

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.

Protein Folding

Protein Folding

Protein Folding

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...

Globular and Fibrous Proteins

Globular and Fibrous Proteins

Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...

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Elastic Moduli of Helical Polypeptide Chain Structures.

S Enomoto, S Krimm

Biophysical Journal

|May 12, 2009

Summary

This study calculated elastic moduli for protein structures like alpha-helix and pleated sheets. Findings suggest the alpha-keratin matrix has an ordered structure with a higher modulus than the alpha-helix.

Area of Science:

Biophysics
Materials Science
Structural Biology

Background:

Understanding the mechanical properties of protein structures is crucial for their function.
Previous models often treated protein matrices as amorphous.

Purpose of the Study:

To calculate the elastic moduli of key protein secondary structures.
To investigate the structural nature of the alpha-keratin matrix.

Main Methods:

Utilized a Urey-Bradley type potential.
Incorporated hydrogen bond stretching terms.
Calculated elastic moduli for alpha-helix, polyglycine II, and pleated sheet structures.

Main Results:

Elastic moduli were computed for various protein conformations.

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Comparison with alpha-keratin experimental data was performed.

Results indicate the alpha-keratin matrix is likely ordered, not amorphous.

Conclusions:

The calculated elastic moduli provide insights into protein mechanical behavior.
The alpha-keratin matrix possesses a higher elastic modulus than the alpha-helix structure.