Past exam of the biochemistry course of the University of Cambridge / 2025 / Paper 5 / Section 2 / 2 / f / Solution

Protein structure can remain similar after extensive protein sequence divergence has obscured a sequence-only relationship. A structural comparison may therefore reveal a conserved protein fold, plausible binding pocket or spatial arrangement of candidate catalytic residues that a direct sequence search misses. Such evidence can suggest a functional family and useful hypotheses.

A similar fold does not uniquely determine function. The same architecture can support different activities, and a predicted pocket does not demonstrate binding or catalysis. Confidence in the model, residue-level chemistry and independent biochemical evidence must be considered together. Structural classification complements rather than replaces sequence and experimental analysis.