Final answer:
A mutation that changes an amino acid's R group from hydrophilic to hydrophobic can affect the protein's primary, secondary, tertiary, and potentially quaternary structures due to the altered chemical interactions between R groups.
Step-by-step explanation:
A mutation resulting in a different amino acid with a hydrophobic R group instead of a hydrophilic R group can potentially affect multiple levels of protein structure. The primary structure is determined by the sequence of amino acids, so a mutation would directly alter this sequence. As a result, the secondary structure may be altered if the mutation affects the local folding patterns such as alpha-helices and beta-pleated sheets.
The change in amino acid properties is most likely to have a significant impact on the tertiary structure because this level of structure involves interactions between R groups, including hydrophobic and hydrophilic interactions, which determine the three-dimensional folding of the protein. Lastly, if the protein is made up of multiple subunits, the quaternary structure could also be affected, because alterations in tertiary structure can influence how these subunits interact.