No, myoglobin is not entirely alpha-helical in structure.
Myoglobin, a protein primarily found in muscle tissue, plays a crucial role in oxygen storage. While it's characterized by a high proportion of alpha-helices, it also contains non-helical regions. Specifically, the single polypeptide chain of myoglobin (globin), which consists of 153 amino acids, is composed of seven alpha-helical segments connected by six non-helical segments (loops or turns). These loops and turns are essential for proper folding and function, allowing the protein to form a compact, globular shape that efficiently binds to heme and oxygen. The presence of these non-helical segments is crucial to the overall structure and function of the protein.
| Structural Feature | Description | Quantity |
|---|---|---|
| Alpha-Helices | Regions of the protein folded into a helical structure | 7 |
| Non-Helical Segments | Loops or turns connecting the alpha-helical segments | 6 |
Therefore, myoglobin's structure is a combination of alpha-helical and non-helical elements, making it not exclusively alpha-helical.
