Proteins usually have hydrophobic interiors or cores and hydrophilic exteriors. If a protein comprises hydrophobic patches on its outer surface,…
Proteins usually have hydrophobic interiors or cores and hydrophilic exteriors. If a protein comprises hydrophobic patches on its outer surface, what can it mean?
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Correct Answer: Option C
Explanation
Hydrophobic patches on protein surface — multimeric complex:The hydrophobic effect is a major driver of protein folding:• Hydrophobic residues (Leu, Ile, Val, Phe, Met) are energetically unfavourable when exposed to aqueous solvent.• Proper protein folding buries hydrophobic residues in the core, away from water.• Well-folded, stable monomeric proteins have hydrophilic surfaces (polar/charged residues) facing water.If a protein shows hydrophobic PATCHES on its outer surface:• These patches represent protein-protein INTERFACE sites.• In a multimeric complex, a hydrophobic patch on one subunit packs against the complementary hydrophobic patch on a partner subunit → both patches are buried from solvent.• This is thermodynamically favourable (reduces hydrophobic surface area exposed to water).Diagnosis:• Hydrophobic patches ≠ misfolded protein (that would be unstable, but the question says it's a valid structure)• Hydrophobic patches ≠ DNA-binding protein (those tend to have positively charged basic regions)Answer: Surface hydrophobic patches indicate the protein forms part of a multimeric complex, with patches forming subunit-subunit interfaces.