An α-helix in a peptide or protein is characterized by hydrogen bonds and characteristic dihedral angles. Choose the right combination. (1) Hydrogen bonding between the amide CO of residue i […]
Tag: CSIR protein PYQ
Tag: CSIR protein PYQ
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Hydrogen Bonding Pattern in α-Helical Polypeptides
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- March 25, 2025
- 28 Comments
In an alpha helical polypeptide, the backbone hydrogen bonds are between (1) NH of n and CO of n + 4 amino acids (2) CO of n and NH of […]
Collagen Triple Helix Position in the Ramachandran Plot
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- March 25, 2025
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The position of collagen triple helix in Ramachandran plot is at- (1) Top Left (2) Top right (3) Bottom right (4) Bottom left Collagen Triple Helix Position in the Ramachandran […]
Dihedral Angles (ϕ, Ψ) in α-Helical Peptides: Acetyl-(Ala)18-CONH2
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- March 25, 2025
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Acetyl-(Ala)18-CONH2 exists in α-helical conformation in solution. Most of the backbone dihedral angles (φ, Ψ) will be. (1) -600, -300 (2) 600,300 (3) -600 ,-300 (50%) and 600, 300 (50%) […]
Understanding Dihedral Angles and Secondary Structures
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- March 25, 2025
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Which one of the statements on protein conformation, detailed below is INCORRECT? (1) L- amino acids can occur in Type l’ ß- turns where ϕ, Ψ are positive (2) A […]
ϕ and Ψ Angles in Right-Handed α-Helices of L-Amino Acids
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- March 25, 2025
- 33 Comments
ϕ and Ψ values for right handed a helix of L-amino acid are expected to be (1) ϕ Negative, Ψ negative (2) ϕ Negative, Ψ positive (3) ϕ Positive, Ψ […]
Understanding Protein Conformation: Key Facts
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- March 25, 2025
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Which one of the following statements on protein conformation is NOT true? (1) Dihedral angles of side-chains in amino acids are depicted in the Ramachandran plot. (2) Infrared spectroscopy can […]
Secondary Structure Regions in the Ramachandran Plot
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- March 25, 2025
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9. The regions of phi, psi space occupied by well characterized protein secondary structures are marked on a Ramachandran plot as shown above. Which of the following statements is CORRECT? […]
Restrictions in the Ramachandran Plot
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- March 25, 2025
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The Ramachandran plot graphically shows which combination of torsional angles phi (φ) and psi (Ψ) of amino acid residues contained in a peptide are possible. Examination of the plot below […]
Understanding Peptides in the Ramachandran Plot
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- March 25, 2025
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Choose the correct statement about peptides in Ramchandran plot. (1) Peptides that are unstructured will have all the backbone dihedral angles in the disallowed regions. (2) It is not possible […]


