Q48.Ramachandran plot is:
(1) Used for determination of stable protein structures
(2) Also called as Φ–Ψ plot
(3) Provide information about sterically favorable conformations
(4) All of these
Ramachandran plot visualizes allowed phi (φ) and psi (ψ) dihedral angles in proteins to assess structural stability and validate conformations. The correct answer for Q48 is (4) All of these, as every statement accurately describes its purpose and properties.
Option Breakdown
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(1) Used for determination of stable protein structures: Correct. It identifies energetically favorable φ-ψ combinations, confirming if a model’s residues occupy allowed regions (e.g., α-helix, β-sheet).
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(2) Also called as Φ–Ψ plot: Correct. Named for plotting φ (N-Cα rotation) vs. ψ (Cα-C rotation) backbone torsion angles.
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(3) Provide information about sterically favorable conformations: Correct. Allowed regions avoid steric clashes; ~98% of real protein residues fall in core areas, outliers flagged as errors.
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(4) All of these: Correct, as (1)-(3) are true; comprehensive validation tool in crystallography and modeling.
Why All Apply?
Developed by G.N. Ramachandran (1963), it maps steric constraints—essential for PDB structure quality checks.
This diagram illustrates φ and ψ angles in the peptide backbone, key to Ramachandran plot interpretation.
The plot shows clustered regions for secondary structures: right-α helix (φ≈-60°, ψ≈-45°), β-sheet (φ≈-120°, ψ≈120°).
Master Ramachandran plot questions like Q48 for CSIR NET Life Sciences, GATE Biotech exams: It’s used for determination of stable protein structures, the Φ–Ψ plot, and reveals sterically favorable conformations—answer (4) All of these. This guide details φ-ψ angles, allowed regions, validation uses, and why every option fits.
Ramachandran Plot Essentials
Plots φ (-180° to +180°) vs. ψ for each residue, excluding glycine/proline extremes.
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Allowed regions: α-helix, β-sheet, L-α helix (no clashes).
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Disallowed: Steric hindrance between backbone/side chains.
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Validates >95% residues in core areas for real structures.
Correct Answer: (4) All of These
No single statement is false; plot integrates all functions for protein quality assessment.
Exam Strategies
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Recall: φ (precedes Cα), ψ (follows Cα); glycine broadens plot (no β-carbon).
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CSIR trick: “All” options often correct if individually true.
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Tools: PROCHECK, MolProbity generate plots for PDB files.
Ace Ramachandran plot used for determination of stable protein structures Φ–Ψ plot—ideal for revision!
