Which interpretations align with the observations concerning the surface amino acids of Protein X?

The correct interpretation regarding the surface amino acids of Protein X considers the nature of the environment in which these amino acids are situated and how that affects their properties.

In aqueous solutions, surface amino acids are primarily hydrophilic because they tend to interact favorably with water. This characteristic is important for proteins as it allows them to remain soluble and maintain their functional structure in a biological context. Thus, the observation that surface amino acids are mostly hydrophilic in aqueous solution aligns with common expectations for protein structures.

When a surfactant like DPC (dodecylphosphocholine), which is used to solubilize proteins, is introduced, the behavior and environment of the amino acids can change considerably. DPC, being a detergent, can disrupt the interactions that stabilize protein folding and can affect how amino acids interact with their surroundings. In this context, some amino acids that are typically solvent-exposed may exhibit hydrophobic characteristics due to the presence of the hydrophobic tail of the DPC molecule.

Therefore, statements regarding surface amino acids being mostly hydrophilic when in aqueous solution (the first interpretation) and mostly hydrophobic in the presence of DPC (the third interpretation) are both consistent with expected biochemical behavior.

These interpretations together