The Structure of Proteins

The Structure of Proteins

Introduction

Campbell and Farrell define proteins as polymers of amino acids that have been covalently joined through peptide bonds to form amino acid chains (61). A short amino acid chain comprising of thirty amino acids forms a peptide, and a longer chain of amino acids forms a polypeptide or a protein. Each of the amino acids making up a protein, has a fundamental design that comprises of a central carbon or alpha carbon that is bonded to a hydrogen element, an amino grouping, a carboxyl grouping, and a unique side chain or the R-group (Campbell and Farrell 61).

Proteins serve a myriad of functions whether within or outside of the cells. These functions include structural roles (cytoskeleton), transport of molecules and ions across membranes, catalysis (enzymes), and hormonal roles. Proteins have structural features that can be described at four levels of complexity. This paper summarizes the structure of proteins.

Protein Structure

Bettelheim, Brown, Campbell and Farrell view proteins as intricate three-dimensional entities whose structural features can be discerned at four levels of increasing complexity (599). These levels are the primary, secondary, tertiary, and quaternary structure levels. The primary structure forms the simplest structures among the four levels. The structure levels become more complex from the secondary to the most organized quaternary protein structure level.

1. Primary Structure of Proteins

Bettelheim, Brown, Campbell and Farrell define the primary protein structure as the series of amino acid groups in a polypeptide chain that have been joined through peptide bonds forming the covalent backbone of proteins (599). This structure usually determines the three-dimension...

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...clusion, proteins have four structural features including the primary, secondary, tertiary, and quaternary protein structures. The tertiary, quaternary, and secondary structures are the results of proteins being stabilized by electrostatic, covalent, hydrophobic, or hydrogen bonds. These structures are the ones that determine the functions of the proteins through their interactions with other molecules. The function of a protein can be changed through denaturation, a permanent and irreversible process in which it is exposed to heat or extreme PH values.

Works Cited

Bettelheim, Frederick, William Brown, Mary Campbell, and Shawn Farrell. Introduction to General, Organic, and Biochemistry. 9th ed. Belmont, CA: Brooks/Cole Cengage Learning, 2010. Print.

Campbell, Mary, and Shawn Farrell. Biochemistry. 7th ed. Belmont, CA: Brooks/Cole Cengage Learning, 2011. Print.