Stabilization of (be unique coiled structure of an alpha helix in a protein is primarily attributed to

Options

A. hydrogen bonding between the peptide backbone atoms
B. disulfide bridges between cysteine side chains
C. carbohydrate moieties attached to polar amino acids
D. peptide linkages that covalently bond amino acids

Answer

**Step-by-Step Solution:**

1. **Understanding Alpha Helix Structure**:
- The alpha helix is a common structural motif in proteins characterized by a coiled shape. It is one of the secondary structures of proteins.

2. **Identifying Stabilization Factors**:
- To maintain the coiled structure of the alpha helix, certain interactions stabilize it. We need to identify which of these interactions is primarily responsible for its stability.

3. **Evaluating Hydrogen Bonding**:
- The primary stabilization of the alpha helix is due to hydrogen bonds. These bonds form between the backbone atoms of the peptide chain. Specifically, the hydrogen atom of the amine group (NH) of one amino acid forms a hydrogen bond with the carbonyl oxygen (C=O) of another amino acid that is typically located four residues earlier in the sequence (N and N+4).

4. **Considering Other Options**:
- **Disulfide Bridges**: While these are important for the overall structure of proteins, they are not primarily responsible for the stabilization of the alpha helix.
- **Carbohydrate Moieties**: These do not play a direct role in stabilizing the alpha helix structure.
- **Peptide Linkages**: These are covalent bonds that link amino acids together but do not contribute to the stabilization of the secondary structure like the alpha helix.

5. **Conclusion**:
- The stabilization of the unique coiled structure of an alpha helix in a protein is primarily attributed to hydrogen bonding between the peptide backbone atoms.

**Final Answer**: Hydrogen bonding between the peptide backbone atoms.

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