The measure of similarity between two structurally aligned macromolecules is:
The measure of similarity between two structurally aligned macromolecules is:
Select an option to attempt
Correct Answer: Option B
Explanation
RMSD — measure of structural similarity:RMSD (Root Mean Square Deviation) is the standard metric for comparing the structural similarity of two macromolecules after optimal superimposition:whereandare the positions of corresponding atoms (typically Ccarbons) in structures A and B.Interpretation:• RMSD < 1 Å: Very similar structures (essentially the same fold)• RMSD 1–3 Å: Similar fold, local differences• RMSD > 3 Å: Different foldsApplications:• Comparing experimental vs. predicted structures• Molecular dynamics simulation analysis (structural drift)• Protein structure alignment (DALI, TM-score also used)Answer: RMSD calculates the average distance between corresponding atoms of two superimposed structures; lower RMSD = more similar.