A LITTLE LIGHTBULB MOMENT
Amino acids, proteins and enzymes
Nonpolar side chains
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Grease-loving side chains hide from water
The idea behind the cue
Nonpolar side chains are hydrophobic and tend to bury in protein interiors or membrane-like hydrophobic environments. Common examples include alanine, valine, leucine, isoleucine, methionine, phenylalanine, and tryptophan; proline and glycine are often discussed separately for structural reasons.
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Short & simple
Grease-loving side chains hide from water
Acronym
HIEE — Hungry Impala Escort Eclairs.
Story
A flock of oily ducks crowds into the middle of a towel and refuses the rain. The water beads up outside while the greasy feathers stay tucked away inside the protein core.
Connect the pieces
- H (Hungry) → Hydrophobic: Nonpolar side chains dislike water and tend to hide away in protein interiors or membranes.
- I (Impala) → Interior: These side chains often bury inside proteins or other hydrophobic environments.
- E (Escort) → Examples: Common examples include alanine, valine, leucine, isoleucine, methionine, phenylalanine, and tryptophan.
- E (Eclairs) → Exceptions: Proline and glycine are often discussed separately because of their special structural roles; hydrophobicity is a trend, not an absolute.
- Hungry · Hydrophobic: Nonpolar side chains dislike water and tend to hide away in protein interiors or membranes.
- Impala · Interior: These side chains often bury inside proteins or other hydrophobic environments.
- Escort · Examples: Common examples include alanine, valine, leucine, isoleucine, methionine, phenylalanine, and tryptophan.
- Eclairs · Exceptions: Proline and glycine are often discussed separately because of their special structural roles; hydrophobicity is a trend, not an absolute.
Know the limits
Hydrophobicity is a trend, not an absolute; local environment and nearby charges can alter behavior.
Further reading · OpenStax science textbooks ↗Check your understanding
Which amino acid is most likely to be buried in a protein’s hydrophobic core? A. Lysine B. Aspartate C. Valine D. Glutamate
A. Valine
B. Glutamate
C. Lysine
D. Aspartate
Reveal explanation
Valine
Valine has a nonpolar branched side chain and is favored in hydrophobic cores. Lysine, aspartate, and glutamate are charged and typically interact with water.