Proteins Secondary, Tertiary, and Quaternary Structures

The secondary structure of a protein describes the type of structure that forms when amino acids form hydrogen bonds within a polypeptide or between polypeptide chains. The three most common types of secondary structure are the alpha helix, the beta-pleated sheet, and the triple helix. 

Describe the secondary, tertiary, and quaternary structures for a protein describe the denaturation of a protein. 

Identifying the Primary, Secondary, Tertiary, and Quaternary Structures of Proteins 

The shape of an alpha helix is similar to that of a spiral staircase. 

FIGURE 16.4 The a helix acquires a coiled shape from hydrogen bonds between the oxygen of the C=0 group and the hydrogen of the N — H group in the next turn. 

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Primary structure is determined, as we ve seen, by sequencing the protein. Secondary, tertiary, and quaternary structures are determined by X-ray crystallography (Chapter 22 Focus On) because it s not yet possible to predict computationally how a given protein sequence will fold. 

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